Right, finally got around to looking at it again and started with a fully charged battery. Started it up, dash light goes out, let it run and check voltage across battery terminals. 13.5 volts and steady, simples! Probably best to keep checking though.
Thanks for the inputs chaps, here's to the next problem.

SteNova said:

matched pair?

Click to expand...

were matched by designation, not manufacture.

been on my disco for a few years now without trouble..










so far