[insert back story here] I have traced the fault to a broken copper link between the solenoid and starter body, can that be soldered? Or will it have to be a new starter?
Image for reference, this is very close to the one I have:
It can be fixed. Somewhere in most towns, near the street of a thousand dodgy car dealers, there is a starter motor & alternator rewinder/rebuilder who can fix it.
Depending on where you are in North Yorkshire, and whether they're still there ('tis a while since I lived ooop North), try Aaron Auto Electrical on Tong Road, Armley, Leeds.