I had two flashing lights at the end of the cycle numbers 2 and 4 from the left.
I phoned Hotpoint and given some answers but essentially they wanted an engineer to look at it for a load of dosh.
I determined the water heater worked by feeling the casing.
I then noticed the top tray dishes were slightly dirty. I positioned the top spray bar in a known position and switched on the machine. After a few minutes I opened the door and the bar had not moved.
Looked at the back tray seal and found the rubber had perished.
Bought new one off eBay for £4 and fixed it in.
No more problems.