OK, so I isolated the machine and went to inspect the front control panel. I found that the panel was only held on to the springloaded arms by one of the existing (pathetic) screws. Despite my long magnet and trawling under the cabinets, I couldn't find the other three, so I dug out some screws to make a temporary repair.
When I took the front panel off, the first thing I noticed was that door closed microswitch was not in its rightful place, so maybe that was causing a problem (or maybe it fell off when I dismantled it). I must admit that I did get some intermittent filling of the machine last night, so maybe that switch was working its way off then. Anyhow, just need to get it all back together/. Probably still won't work, but SWMBO is after a new kitchen in the New Year and told me that if the dishwasher is fubared,
we'll I'll just have to wash up by hand until then. So, this is serious, folks!!