Hotpoint WMT01 door light flashing after 20sec. fill.

I put new brushes in this a month ago. Customer has just rung to say, “we have the same fault again.” Oh yeah :rolls: .
Anyway, I got him to give me a bit more detail and he switches on, programmes up a rinse, machine fills for 20 seconds or so and then the “door light” flashes continuously without pause at the usual sort of 1/sec. rate. I presume it stops filling at this point and will go no further.
He did also say he had tried it on a slow spin and it turned but did not gather speed.
It has just occurred to me that we had a thunder storm on Saturday evening. Wonder if their house got struck; it is quite high up.
Going Weds afternoon so plenty of time to contemplate. Any ideas appreciated.
Mike.