Yes, sorry. He's a bit tricky to pin down as I don't think he described what was happening accurately, and wanted to be told what he wanted to hear. Which was that the elements had gone - he's now replaced them and I think now is all well.
I've just sent him an email asking to set out what the symptoms/cure was - but I don't expect a straight answer. Whatever, i'll pass it on - thanks for all the feedback.