Got the dreaded AL01, and indeed the base was flooded. Looked carefully, saw no leaks…
Cause was the lower rotor arm – the upright hollow plastic post had come unscrewed from the floor of the machine (and hence let water into the base).
Tightened it up, removed the water and still AL01. You have to press reset til you get all dashes, press off, press off again, and you’re back running.
I daren’t tighten with pliers in case I snap the post – will just check it regularly. Not the cleverest design…