These are the measurements:

Seat tube (c-t) = 58cm, (c-c) = 56cm
Top tube (c-c) = 56cm
Chain stays (c-c) = 41cm
Head tube length = 152mm
Rear spacing = 126mm
Seat post dia. = 27.2mm
BB = Italian thread 70mm

I initially just wanted to get a group that would make it period correct but thought I'd add a more modern drive. My LBS can cold set the frame.

Thanks for the responses. Much appreciated.