West side of London Road opposite Inglemere Road.
Google Street View’s history shows that between 2008 and 2018, it is a barber shop.
In 1983, a motorcycle shop as shown on this receipt:
Unit 2, 339 London Road. Possibly since 1980s.
MGM are the initials of M.G. Mordecai, see invoice below:
See current website for MGM Tyres and MOTs.