Hotpoint DYN 9164DPG/L 1-80 F 15 Fault not reset by power cycle

Hello, struggling with a Hoover! not Hotpoint, (the gift of Dislexia) DYN 9164DPG/L 1-80 which after moving program selector after pressing start , it came back with an F15 Fault that wont reset without power cycle, and i have left plug out for hours
Just before it Faulted the water solenoid opened for a second and Door locks , since then nothing much, after switching on a few seconds later the F15 comes up (did flicker second time) and door locks but nothing else .
the door switch has been a bit hit and miss recently as need to make sure its firmly closed to start cycle but this never through up a fault code, it just did not start
i HAVE CHECKED

The inlet water pressure , good , filter not blocked etc
The drain pipe and pump, all clear
The connections, Been round and given them all a wiggle and made sure there home .I did find the heater wire broken off at back of Lucar spade connector ,but made no difference . It has only just broken as i have been checking the power consumption on new electric meter , about 3 KW
the pipe to the pressure is clear from blockage .
So last thing may be i have corrupted the board by turning program knob just after pressing start switch? if so can it be reset? or is it a new board which i guess will right of the machine?

Is there any switching procedure to pin point or reset faults on this machine?

I have had a few problems in the past , machine stopping near end of cycle with a drain fault (F04) that turned out to be an electrically leaking heating element , found this after changing drain pump and pressure switch

Any advice gratefully received Thanks in advance Gordon