Volvo S40 Intermittent Alarm Problem

For the last few weeks, the Alarm has gone off unpredictably in any period
between a few hours and a couple of days if the car's been parked that long.
It sounds for about a minute, resets, then may not go off again for many
hours more.
It's a 1998 S40 1.6xs and always kept in my garage. I haven't noticed the
alarm light indicate fault by rapid flashing as mentioned by someone
elsewhere last year.

The battery is good and terminals clean and tight. I'm unsure where the
exact alarm fuse or alam unit are located but obvious connectors, bonnet
microswitch, operation of door and boot switches all seem fine.

Is there any known issue with the S40 Alarm system?

Does the system record alarm events and what triggered them?
If necessary, can the alarm be disabled?

Any advice appreciated.

Regards,

Ide