That's a really big ask for a truck that old. The TK I'm doing up was made as late as 1980 and some parts are still almost impossible to get.
Google is your friend, try to find an owners club or maybe other people working on the same model. Certainly worth asking Robert at
www.bedfordtruckparts.co.uk he is a mine of information and has many useful contacts.
Autojumbles and other gatherings of folk working on vintage trucks?
Looks hopeful -
www.vintagebedfordspares.com