Wow thanks for all the responses, never fails to amaze me how much knowledge is out there!

Bertinjim: I can't see / feel any seams though didn't have a flashlight handy so will try again tonight. Feels pretty smooth though

Repechage: can't see any such markings on the dropouts , though the inner surfaces are a bit worn. Could only find a 'o' on the bb shell , though all the lugs have a number on so it may refer to the bb shell?

I did find s.v 980 on the fork steerer, I'm guessing this means super vitus 980? If so I wonder why the Reynolds sticker, is it likely to have a different material for the steerer?

I think my next free weekend ill swap out my gitane frame and see how this one feels....anyone in the uk got a spare french headset ?!!

Thanks again!