3 different places
Chasbikes near Waterloo, he does all the couriers and is sympathetic towards scruffiness and loud exhausts
Gordon Swift Motorcycles near Basildon - 2 old boys working out of a small garage in a residential area, well worth a trip just to see the classic bikes they have there, if you need a part for a BSA or a Goldstar chances are they'll have a clean second hand or new old stock part, also a bit mutton so not bothered by loud exhausts.
Elm Park Garage on the A1306 near Rainham, car dealer really but likes old scooters and understands that 1960's brakes were shite so tests accordingly.
All recommended.