As a follow on; I visited Graham Foot today at Slam69, he and his partner were pretty pleased to see the frame, and he confirmed that the BB is Italian 70mm.
This is a cautionary tale to those who assume and who don't use there eyes and their vernier calipers (or just a steel rule). Below are pictures that show what happens when you install a British / ISO bottom bracket into threads designed for a more unusual (in MTB's) sizes.
The force that must have been required to make a LEFT HAND thread fit a RIGHT HAND shell, don't bear thinking about it.
There is an old engineering truism 'if you have to force it, you're doing something wrong'
Graham is hopeful of being able to carefully chase the damaged threads out. The alternative is a sleeve or a threadless BB.
This could so easily have been avoided, and the thread running continuously from side to side of the shell should have been an immediate give away.
Ah well, with any luck we shall soon have it fixed.
BTW, the gold Bigfoot in the Malvern photo's shown on other threads is Grahams own bike that he still has. He also knows of the very last bike sold, just before he shut up shop. It is still local and is almost never ridden, but is perfectly preserved.