Truma Combi E CP Failure

Whilst away last week the 230v heating side of our Truma Combi E failed. Thankfully we could still use gas without a problem. On return home I spoke with my usual service engineer who, whilst he couldn't get over to see me talked me through what to check. It turns out it is one of the fuses on the unit that had blown. This fuse is not immediately easy to check as it has to have the main (screwed on) panel removed. The obvious question was why had it blown? Was it a power surge or a failure of the electronic system further down the line. The suggestion was that it may be the anti surge resistor on the PCB adjacent to fuse or worse still, the heating elements. I'm hoping it is not the latter as I had them replaced at a massive cost three years ago and they have only been used for 140 days since then. 

Although they are a 'special' fuse they are readily available which suggests failure of just the fuse is fairly common. What surprised me is the wide range of prices for the fuse, from less than £1.00 to Truma's £25.00+  for a fuse. For the technical ones amongst you it is a T10AH fuse according to my Truma trained engineer. If replacing the fuse doesn't sort the problem, I'll have to think again.

The question is, has anyone had to have their PCB changed (the lower one of the 2 where the 230v is connected). If so, how much was it? As an alternative to replacing the PCB I'm go see if the anti surge resistor can be replaced. I know a good electronics guy at Burton upon Trent.

I'd be interested to read comments from anyone.