So in a brief interlude between showers yesterday, I plugged in the laptop to discover, as suspected, a front sensor issue. NSF one, short to 0v.
When it initially happened, like DG, wondered if it was air suspension or compressor, but slowly moved away from that when the ride height on all corners looked normal, even when putting all the stuff in the boot to come home (and Mrs TB does like to take the kitchen sink with her!).
Popped over to Gixer's gaff to use his dry garage to avoid getting wet again, and checked the condition of the exposed part of the loom in the wheel arch, and if the connector was dry. The outside of the connector was wet, but the important bit was dry.
Live data was showing the voltage changes when jacking up the suspension an inch or so via brake disc - car was already jacked up.
Went over with a hairdryer anyway, and a bit of vaseline around the seal, but still showing a fault. Distracted by one of Mrs Gixer's late breakkies, then the qualifying, then the footie, ordered a cheap sensor that I'll replace when it arrives.