Zanussi built-in Washer Dryer – ZWT71401WA – E10 error

I checked online about this fault before visiting…. pulled the machine out, checked both hoses to be fine and no blockage in drain, lifter cap at the rear top of the soap box to confirm water was flowing on dry setting which it was, so then started a dry cycle….. it performed all the functions and I left it on for around 20mins (longer than when cx said it failed) but I found no errors.

3 days later and after 2 good dry cycles it fails again, showing E10…… Any ideas please?

PNC – 914606039-01
SER – 73400112