Thanks for your tip Keethos. No problems overnight (thank goodness) and no problems today, but done 68 miles in it today, so battery should be well charged.
I'm wondering if I accidentally hit an alarm button or two when I was chucking stuff into the glove box, which may have resulted in the the sensitivity being reset.
All I can do for now is keep an eye on it, or perhaps an ear would be more appropriate.
Appreciate the reply,
Fenhopper.