Was a few issues. But quite straight forward in the end.
- I never really questioned the integrity of the 2 year old Bosch battery. However, it was a goner, only holding 30% capacity. Of course having trouble getting it replaced on Bosch's 3 year warranty. Bought another one and will try to swindle something in the future
- The valeo alternator I'd got on ebay, just my luck, was working fine when I fitted it, and continued for the 1st year or so. But clearly it's brushes/regulator are gubbed. I bought a replacement regulator housing and slip ring yesterday from a nice autoelectric shop here in Glasgow. Prolek is the place, I recommend them for friendly advice and good prices.
Will get the Alt reconditioned and new battery in and fingers crossed, all will be well
I hope all the other fiddling about, cleaning wiring connections and earth contact will reduce the chance of something else going wrong in the future.
Thanks for all advice.