classic motorcycle forum

I believe it was used in an early tank too. Far better mechanical device than those French derailleurs!
The bloke making them for Scotts apparently isn't taking any more orders at present, either because he's snowed under or stopped doing it. Over-egging the pudding I think personally. The old Pilgrim, for all it's alleged faults, has worked well-enough on Scotts for decades.

Sorry to contradict you Rex, but  but the Post office did respray their own vehicles, there used to be a place near Kidbrooke S London that did it and the red spray dust out the vents was noticeable.  I also knew a guy who had worked there, coach painting with a brush at times.

Kidbrooke was one of the (if not the) biggest stand-alone GPO vehicle depots in the country though, and God knows how many vehicles, including artics, passed through there in a year.
Not really the same as the vehicle workshops and depots attached to sorting offices, mail centres etc  all over the country though. As I said, small scale repairs only, and as space was invariably tight there wouldn't have been room for either a spray booth or racks to hang the repainted frames, tanks etc etc from anyway.
As has been said, a fleet purchaser such as the GPO/RM could have any colour they liked.
 They also used to screw BSA (and later other suppliers like Puch, BL, Austin Rover, LD Vans etc) to such a degree that some firms were unwilling to supply them.

My old Empire Star had one of these carbs but I never found it problematic.
If there is a problem then the long-throat 276 (as used on various MO1L equipped singles) is a possibility?

There is an organisation for ex-GPO/RM vehicles and I'm sure a little Google time would discover it. Everything from push-bikes to small lorries so I'm guessing they could help you.

If he waits for the correct parts to turn up he'll probably be retired before he finishes it, so the best option is to make or modify parts to fit, and then replace the "incorrect" parts as originals turn up (if they ever do!).
Mudguards, lights, speedo (if it ever had one) switches and petrol tap are generic items, and the mag and wheels should be adaptable from something else without too much hardship.

If you mean the pig farmer, then yes, be very wary, especially if buying sight-unseen. He's not averse to a little rattle-can silver or black to make his offerings look better in the pics, but that said, he does have some nice stuff even though most are adulterated with metric threads and fasteners.

Thanks for the detailed reply mate. After a lifetime working with Amps and Volts the original Villiers lighting set-up holds no fear, but I'm interested in the modern electronic upgrades you alluded to.
Getting the lights working isn't really a priority, but if I get hold of a lighting coil I'll wire it all in, but if they're difficult to obtain then LED globes front and rear fed of a Cyclon battery (hidden in the toolbox or whatever) would be more than adequate.
First job is to sort the dragging clutch. The last bloke had a reline by Villiers Services but clearly it now needs setting up better as it drags enough to stall the engine and there's a ton of slack in the cable/lever too.
According to info found on the Net, it started life as either a G24 150cc or a G25 200cc. Shame that some sod sold off the original 2-letter four-number reg number though.