X308 door locks nervous breakdown

My Sovereign was working so well that I got out of the habit of following j-l (my bad…). And then the other day I took the kids to school and when I got back to the car:

(1) the fob wouldn’t work
(2) the key unlocked all four doors (good, so far)
(3) engaging ‘drive’ locked all doors (good, so far)
(4) pressing the lock/unlock button on the dash board didn’t do anything
(5) the dashboard claimed the boot was open (it wasn’t)
(6) the dashboard claimed there were failed rear bulbs (there aren’t)
(7) Opening the driver’s door from inside did not cause the other doors to unlock as it should
(8) The boot lid button wouldn’t open the boot
(8) the fob wouldn’t lock the car

Next morning, everything was back to normal. The following day the whole thing happened again, and it’s now stuck that way. I have tried ‘re-booting’ by disconnecting the battery and shorting the cables for a few minutes but no change. I am thinking that a module has failed but hoping against hope there’s a simpler, cheaper, possibility…

The car drives fine (or will do once it’s re-learned its engine/gearbox optimisations) but the flashing messages on the dashboard are pretty distracting.

Justin