Just thought I'd share my recent experience with you. The tailgate central locking stopped working, but when I put my hand on the tailgate and someone else operated the central locking, you could feel the "thunk" of the solenoid operating. The lock still locked and unlocked with the key. Anyway, I removed the rear panel, peeled back the moisture barrier to find that twenty plus years of locking and unlocking had vibrated both the retaining nuts off, allowing the solenoid to dangle within the rear tailgate. A quick bit of manoeuvring and two spare 10mm nuts from the toolbox and the job's a good 'un. Try as I might, I could not extract the lost nuts from the bottom of the tailgate, and each time I open it, they rattle to remind me...
Couple of photos to show the solenoid out of place and then back on before the nuts were applied
