John Lewis Tumble dryer error code E60 & E65?

My John Lewis tumble dryer (JLTDC01) has been showing the error message E60. It runs a cycle and then shows the code E60, the clothes are damp and warm. It had been making a low rumbling noise. (it's a condenser dryer with heat pump). I've cleaned the filters and jet washed the condenser.

I can't find anything on the internet except to select a programme and hold the two buttons to the left and the error message E65 comes up. I guess E60 is a general error code and E65 is what is wrong but I can't find what this means.
I understand that this machine is based on a Zanussi machine.
Can anyone help?