Hi Guys
Apologies - my ZT has been on the hoist at work for far too long with this problem, but I have a mired of other problems to sort out and "forgot" to come back to the thread. (a utility fell off a hoist last week - not a good sight - no-one injured, thankfully!).
Anyway, my electrician says he will give the repair a go, but seriously requires a wiring diagram to know where to start his trace... Another electrician up the road won't even entertain the thought of looking for the fault!