I remembered reading a forum where a man with a different machine had written about his reset buttons. On his machine, he had to hold in the two reset buttons while he switched on the power, so I tried it that way.
The pump didn't come on, the third and fourth switches lit up and stayed on. I powered it down, then when I put the power back on, it acted quite normally - no pumping and one function switch lit, which I could select between all programme buttons. Just normal.
I have since then run a rinse cycle and a regular 50 wash, all okay.
Maybe it was stuck in a logic loop after all. I don't understand why a different way of using the reset buttons would work, I'm just glad it did. It's fingers crossed from now on, but I won't any longer be opening the door part-way through a cycle. It just isn't worth the risk.
Thanks, NomadPaul, for your involvement.
As an aside, when I was taking off the base board and decor panel, I noticed a few things that the builders could have done better. For example, they did not install a plate that is supposed to be fixed to the underneath of the worktop, above the dishwasher door. I have a digital version of the installation instructions that shows it should be there.
What it doesn't show is a part number or name for any of the parts. Does anyone have a parts list? Or can you tell me what that piece is called?
Also, they had the three dishwasher feet sitting on blocks of wood. I took one of them out and lowered that foot to the floor, and that is about 80mm. The diagram shows it should be 0 - 60mm. I don't want the feet falling off, but I don't know how long they actually are. Surely they wouldn't make them so short that, to fit into a normal height of counter, the machine would have to sit on blocks?
As before, any help would be much appreciated.