Yep thats about it,

As for using a voltmeter, there shouldn't be any issues with shorting things out

James how far are you from Lambourne. I am over there on Sunday taking the engine out of my TZR.
I could pop over and try a few of the things I suggested.
I was suggesting adding a seperate earth to somewhere on the back of the clocks to see if there is a earthing problem, I could also bring my Multimeter and check out a few other things.

Skidlids, I live about 10 miles form Lambourne, SN6 6JS is the postcode. I am in most of the day Sunday apart from between 1.30 and 3.30 (sons football match). I would really appreciate it if you could help me.
Let me know if you can come and I will give you directions

Roachman