Daniel Suddaby asks ":...a 50's Gillott Fleur de Lis ...I would like to get a view on the most suitable components that would suit this lovely frame, my aim would be for authenticity to the age and efficiency for speed (lightweight). I thought campag goup set and mavic wheels but that's as far as I have got, any of your expert thoughts most welcome?"
if you wish to set it up similar to a British bicycle in the 1950s, look through photos and details of various 1950s bikes on the Classic Lightweight UK site.
http://www.classiclightweights.co.uk/
In the aggregate, you will see what was mounted on 1950s bikes, though not all of those bikes may be precisely period correct in all their components.
As for Campagnolo, there were several types of Campagnolo Gran Sport rear derailleur that appeared throughout the 1950s, so you should check Chuck Schmidt's Campagnolo Timeline to see which one would be period correct for the year you are aiming.
Peter
Peter Brueggeman
La Jolla California USA
4peebee(at)peterbrueggeman.com