Unit 2, 339 London Road. Possibly since 1980s.
MGM are the initials of M.G. Mordecai, see invoice below:
Invoice from 18th July 1985
See current website for MGM Tyres and MOTs.
MGM Automobile Engineer
Mitcham History Notes
Some notes about history of Mitcham, Surrey
Mitcham History Notes 
They are still going and have also taken over Mitcham Tyre Mart.
RegardsAlan
LikeLike
yes, as stated in post for Mitcham Tyre Mart : https://mitchamhistorynotes.com/2019/01/16/mitcham-tyre-mart/
LikeLike