Thanks for all your replies on the Freddie Grubb tubing.
I've got another question on the bottom braket - namely will a bike of this era (50's) take a modern bottom bracket eg Shimano UN72 or will it require an imperial size. It had a bayliss cottered braket in it and I want to go cotterless. I've got a set of zeus 165 track cranks which I'm going to use and intend to use a 109-110 spindle.
Any thoughts would be gratefully appreciated.
Thanks
Stewart