OK, here's a follow-up.
I checked the drum motor brushes - both fine.
Checked the water level switch and pressure switch - both fine.
Checked the control PCB (on the sidewall, near the base) and found a charred 110ohm/5W wirewound resistor. I replaced it with a new one (thanks Maplin), and re-assembled, but it burnt out in the first couple of seconds of when the drum would have started to agitate (without the drum moving even a twitch).
So, it looks like the burnt resistor is a symptom, not a cause. I'd like to think the problem is somewhere else on the control PCB but it'd be hard to diagnose (microprocessor onboard) and if I simply replace it and the fault is elsewhere it could be a costly experiment ...
Any ideas anyone?
Thanks
Sar, October 2005