Question Author
Hi,
Just to update & put this one to bed as someone might find this useful - it cost £70 odd to have an engineer visit to tell me he thought one of the 2 PCBs needed replacing tho' couldn't be 100% sure. This wasn't a Zanussi Service Force engineer btw, they want their call out fee before they visit ! He estimated a new PCB could cost £100s but was going to find out how much & let me know. He never actually did (so not impressed) but meantime I contacted Zanussi direct. Turns out they run a "contribution exchange" scheme where they'll replace a machine with like for like, at trade price, taking into account how old the faulty machine is.
They gave me the option of 2 machines, updated versions of the one I had, for £180, with free delivery & disposal of old. They cost £300+ online so for a total of £250, I've now got a new machine & warranty. Replacing the PCB would likely have been the same (if not more !) so good result I reckon.