Thanks Pizzaguy,

I have seen the considerable stuff on this forum about the alarm issue so I first checked the siren and replaced it with one from needs wings. The alarm still triggered - perhaps less often - and now it sounded crisp and loud, rather than the dying cricket.

I read a lot about the boot moisture issue so I did get down to the CLP/SSM and totally expected to see signs of moisture - like electrical corrosion - but didn't. The CLP was dying, as the locks took time to close, so as mentioned in my post I replaced the whole thing with this: https://www.needswings.com/central-locking-pump. All locks now close crisp and sharp.

I did not consciously check each connector for corrosion though, so I will do that - although its a darn pain to get back in there! I think I would have noticed corrosion in the connectors though.

How possible is it, do you think, that its a faulty actuators in the doors, fuel cap or trunk door?