Ariston LSI61 not able to select wash cycle

I have an 8yr old Ariston LSI61 which tripped my RCD during a wash cycle. LED panel reported ‘flood protection’ mode, so I checked underneath and sure enough a few mm of water in there.
I’m pretty certain the water came from earlier in the week when I topped up the salt (the bottom washer came up due to my fat fingers and some water ran down). I emptied and dried the water and no more flood protection warning.

I ran the short test (1010), no RCD trip and no errors at the end.
I ran the long test (0010), no RCD trip and no obvious errors either (apart from the detergent dispenser which hasn’t opened anyway for months).
I.e.
1000 Fill Solenoid Valve OK
0100 Wash Pump OK
1100 Heating Element OK
0010 Detergent Disp DID NOT OPEN, but hasn’t for months
1010 I/Sol regen OK (not sure what this is, but it seemed to be successful)
0110 Drain Pump OK
1110 Fill Sol OK
1100 End OK

My only remaining problem is I cannot run a normal program. None of the four LEDs light when pressing the ‘P’ button in user mode. I can boot into diags again and select the LEDs to run a test cycle, but nothing in user mode.

After speaking to Nige at GT Electrical, I tried disconnnecting the dispenser to see if that helped, but it made no difference.

Any other ideas? If it comes to changing the PCB and dispenser (£100 ish altogether ) l’ll probably buy a Bosch instead.

BTW Nigel at GT Electrical is fantastic. I found him via the repairs@ system here. Can’t rate him highly enough.