Tyres etc. service since 1934.
Listed as 408 London Road in the 1952 Chamber of Commerce, the 1971 telephone directory and shown in this ad from 1963:
Proprietor A. PAYNE
According to the MGM Services website:
When the owners retired around 2013 the premises of Mitcham Tyre Mart at 339 London Road, CR4 4BE, were taken over by MGM.
See also MGM Automobile Engineer