Hi Andrew,
They don't specialise in old bikes, but Stows in Slough are my lbs of choice.
Jan there likes to work on older reliable parts.
If you go there, tell him Richie recommended you use them.
He has one of my rear wheels to true and service the hub (C Record bearings shot) that I'm collecting this weekend.
Richie
Thanks, Richie. Good point, I've had great service from Stows in the past (and they have that smashing gold centenary Raleigh wotsit hanging up to look at).