Ariston AFA350 Pump sticks on / flashing light

Hi all.

As the title says I have an Ariston AFA350 dishwasher.

Here are the symptoms:

Sometimes washes fine and then instead of finishing the cycle goes back to the intial light which starts to flash instead of the last light (usual indication of end cycle) Manual says consult engineer no further help.

Also the drainage pump continues to run………….until you turn machine off. Reseting and switching back on; the pump fires up again even with the swith left at reset. Turning to a cycle has zero effect.

What I have tried:

Checked pump not blocked by manually filling machine with water and checking it drains. Once wwater drains pump continues to pump air (suspect this is bad for the pump)

Taken off front door panel and examind simple rotary switch. But all back together and made one cycle of wash but pump remained on at the end.

Now suspect the control board but before I spend £50 on one I wanted to see if there was any kind of switch at the pump or if the control board did it all.

Ideas?

Thanks in advance
Sean