Isis dishwasher DW250 overflowing

Anyone had any dealings with these?

I went to it 7 weeks ago; it had overfilled to the point of flooding under his cupboards until it found a plug and tripped his RCD.
I couldn’t find anything wrong, but suspected a possible loose connection on the impellor reed switch.
It worked fine on functional checks, so he was happy to monitor it.

7 weeks later, and it’s gone and done it again.

I suspect it’s a Homebase/Chinese venture that’s a right pile of rubbish, but he’d like it fixed.

Any ideas, please?
(And does anyone know of where to obtain any necessary parts for it?)

Thanks,
Pigpen.