From Wikipedia:

Sir Harry Deeley Mallaby-Deeley, 1st Baronet (27 October 1863, London – 4 February 1937, Cannes) was a British Conservative Party politician.

Harry Deeley was educated at Shrewsbury School and Trinity College, Cambridge. His brother was the theatrical producer Frank Curzon.

…

In 1913 he purchased the whole of the Duke of Bedford’s Covent Garden estate for £2m., having already been involved in the purchase of the Piccadilly Hotel and St. James’s Court, Buckingham Gate.

In 1922 he famously acquired control of the large estates of the cash-strapped Duke of Leinster during the latter’s lifetime. Fitzgerald had previously sold Mallaby-Deeley his reversionary rights to the estate for a notional consideration, not expecting, as a younger son, to inherit.

Deeley was elected Member of Parliament for Harrow in 1910 and for Willesden East in 1918, resigning in 1923. In 1922 he assumed the additional name of Mallaby, his mother’s maiden name, by deed poll and was created a baronet.

Although the wikipedia article cited stated he was founder and first president of the Prince’s Golf Club in Mitcham, it has been pointed out that this was not the case. The following has been provided to correct this error:

Prince’s Golf Club Mitcham was formed by members of the Prince’s Racquets and Tennis Club of Knightsbridge in 1891 with Robert Hippisley Cox the prime mover. The first President was Arthur Balfour M.P.

Mr Mallaby Deeley came rather later and in 1900 had risen to the position of chairman. The Prince’s Golf Club Company Limited was restructured, went into voluntary liquidation and the same day a new Prince’s Golf Club Company Limited was formed with Mallaby Deeley as controlling shareholder.

Source: information available at the National Archives

News Articles
From the British Newspaper Archive which require a subscription.

1937 Obituary

Sir H. Mallaby-Deeley

During the twelve years he sat in the House of Commons Sir Henry Mallaby-Deeley was content to be for the most part a silent member. He was a picturesque figure, and regular in his attendance, but his friends were always a little puzzled to understand why he cared to belong to an assembly in whose affairs he took little active part. His name came frequently before the public in connection with gigantic transactions in real property—among them the purchase of part of the Bedford estates, at a cost of about £2,000,000, and the Foundling Hospital site, most of which has since been re-acquired for preservation as a children’s playground. A much more surprising venture, and one having no relation with his other interests, was his opening of a shop in the Strand for the sale of men’s clothes at about half the prices then prevailing for readymade suits. As was to be expected in view of his lack of experience the enterprise was a commercial failure, and he admitted having lost about £60,000 during the two years it – was carried on. He claimed that the experiment was worth while for the sake of the stimulus it gave to others with a better knowledge of the trade to reduce their prices. Sir Henry was a keen golfer, and, among his many enterprises, he controlled the Prince’s course on Mitcham Common, now under municipal direction, as well as the Prince’s course at Sandwich.

Source: The Scotsman – Saturday 06 February 1937

1936

SIR H. MALLABY-DEELEY MARRIED
Private Ceremony a Month Ago

It became known on Monday, says “The Times” that Sir Harry Mallaby-Deeley, Bt., of Mitcham Court, Surrey, was married on December 9 to Miss Edith M. Shoebridge, his private secretary.

The arrangements were made so quietly that even the household staff at Mitcham Court were not aware that on the day when Sir Harry Mallaby-Deeley left for the Continent Miss Shoebridge was going with him as his bride. The marriage took place by special privilege in the Bishop of Southwark’s private chapel at Bishop’s House. Kennington, the Bishop officiating.

Sir Harry Mallaby-Deeley made the acquaintance of Miss Shoebridge a little more than a year ago. She had been private secretary to Lord Derby. Sir Harry Mallaby-Deeley was first married in 1890 to Miss Joan Parson-Smith, who died In 1933. and has one son. He is well remembered In Chester as a son of a once prominent citizen, the late Wm. C. Deeley, a director of the Dee Oil Company. Saltnev. and a onetime chairman of the Chester Liberal party.

Source: Cheshire Observer – Saturday 11 January 1936

1933

LADY MALLABY-DEELEY DEAD

Lady Mallaby-Deeley, wife Sir Harry Mallaby-Deeley. Bart., the financier and former Conservative M.P. lor Harrow and East Willesden, has died at Sir Harry’s Surrey home, Mitcham Court. She had been ill for only a week with bronchial pneumonia. Lady Mallaby-Deeley, who was formerly Miss Joan Parson-Smith and a member of a well-known Shrewsbury family, was married to Sir Harry 43 years ago. There are four children, two sons and two daughters.

Source: Gloucester Citizen – Wednesday 20 December 1933

SIR HARRY MALLABY-DEELEY Bart., of Mitcham Court, opposite Mitcham Cricket Green, and a Mitcham Conservator, is credited with one of the most important property purchases in London of recent years. Sir Harry has bought the whole of the interests of the Foundling Estates, Ltd., in the Foundling Hospital estate in Bloomsbury. The estate consists of 34 acres, exclusive of streets and squares, and the total price is stated to be in the neighbourhood of £1,750,000.

Sir Harry and Lady Mallaby-Deeley left for the south of France on Saturday. For more than 25 years Sir Harry has been one of the most striking figures in London finance.

In 1924, Sir Harry handed over to the public Prince’s Golf Club, Mitcham. He has given large amounts to charity, notably £15,000 to the London Hospital. He was Unionist Member for Harrow, 1910-18, and for East Willesden, 1918-22: He was made a baronet in 1922. One of his most famous deals was with the Bedford estate in the Strand a number of years ago now.

Source : Mitcham News and Mercury, 14th April 1933

1910

West Sussex Gazette – Thursday 20th October 1910

Mr. H. Mallaby-Deeley, of Mitcham Court, has just bought-up the whole of St. James’ Court, Buckingham Gate. This parcel of property consists of eight blocks of flats, with a present yearly rent roll of £30,000. It is understood the price paid was in the neighbourhood of a quarter of a million.

Mr. Mallaby-Deeley was the buyer of the Piccadilly hotel, for about £500,000. It is said he is now building a mansion at Harrow, and will shortly be leaving Mitcham. He is the controlling spirit of the Golf Club, and chairman of the Common Conservators.

Croydon Advertiser and East Surrey Reporter – Saturday 29 January 1910

A MITCHAM M.P.

MR. MALLABY-DEELEY RETURNED FOR HARROW.

The campaign in the Harrow Division of Middlsex was followed with considerable interest by Mitcham because the fact that the Conservative candidate was Mr. H. Mallaby-Deeley, ot Mitcham Court. opponent was Mr. Percy Harris, a well known London Liberal, and the fight was a very keen one. Polling took place on Monday, and the result was declared about two o’clock on Tuesday as follows :

Mallaby-Deeley (C.) ...,. 16,761 
Harris (L.) ............. 13,575 

Conservative majority ... 3,186

This was a Conservative gain, the turnover of votes amounting to less than 3,602. The new member is a director of the Norwich Union Life Insurance Society, a governor of the Whitgift Foundation, Croydon, and Chairman of the Mitcham Common Conservators, and one of the principals of Princes Golf Club.

Though there are more popular men at Mitcham than Mr. Mallaby-Deeley, there are none more striking in their personality or more keen in a business capacity. It is not expected that his Parliamentary duties will interfere to any great extent with his work Chairman of the Board of Conservators.

From the Surrey Coats of Arms:

MALLABY-DEELEY Sir Harry Mallaby Mallaby-Deeley, 1st Bart., JP, MA, LL.M (Cantab), of Mitcham Court, (1863-1937), was
created Baronet 1922. The title expired on the death, 1962, of his grandson Sir Anthony Meyrick Mallaby-Deeley, 3rd Bart., of Slater’s Oak,
Effingham.
Arms: Quarterly, 1 and 4, Sable a chevron engrailed Ermine between in chief two fleurs-de-lys and in base a crescent Or (Deeley);
2 and 3, Or a bunch of nettles Proper and a chief Sable (Mallaby).
Crests: 1, A sinister cubit arm in armour gauntleted holding in the hand a dagger point downwards Proper pommel and hilt Or
between two spurs Gold (Deeley); 2, Issuant from clouds Proper a demi Pegasus Argent winged and charged on the shoulder with a fleur-de-lys Azure.
Motto: Quod Deus vult. (BP99)

Motto means What God Wills.

From Debretts Peerage of 1923:

Sir HARRY MALLABY MALLABY-DEELEY,
M.P., 1st Baronet, second son of the late W. Clarke Deeley, of Curzon Park, Chester, by Elizabeth, da. of Joseph Mallaby, of Loxley Hall, Staffordshire ; b. Oct. 27th, 1863; ed. at Shrewsbury Sch., and at Trin. Coll., Camb. (B.A. Honours in Law and LL.B. 1885, M.A. and LL. M. 1888); is Lord of the Manors of Ravensbury, Biggin and Tamworth, a Member of the Inner Temple, a J.P. for Surrey, a Director of Norwich Union Life Insurance So., a Gov. of Roy. Agricultural So. of England, a Member of Committee of Roy. Orphan Asylum, Chm. of Board of Conservators of Mitcham Common, and patron of five livings; sat as M.P. for Harrow Div. of Middlesex (Co.C) Jan. 1910 to Nov. 1918; elected for E. Div. of Willesden Dec. 1918 and Nov. (C) 1922; assumed by deed poll (enrolled in College of Arms) 1922, the additional surname of Mallaby: m. 1890, Joan, third da. of J. Parson-Smith, J-P-, of Abbotsmead, near Shrewsbury, and has issue.

Seats — Mitcham Court, Surrey; Elgars, Bexhill, Sussex.
Clubs – Carlton, Wellington, Surrey; Magistrates’; United Empire; Royal Automobile.

SON living — GUY MEYRICK MALLABY, b. May 23rd, 1897 ; ed. at Trin. Coll, Camb,, and at R.M.C.; Lieut. 5th Dragoon Guards : m. 1920, Marjorie Constance Lucy, only da. of James E. Peat, of Cranmers, Mitcham, Surrey.