Many thanks for the advice - actually a switch in the loft would be ideal. I've not had a chance to do anything with it yet, but may well install one when I do.
This relates to a 9448 scantronic alarm - installed in 2007 by the looks of it. Following a failed main battery recently, which also took out one of the PCB fuses, I'm getting more familiar with the panel internals. However, the pathway to my enlightenment did involve waking up the neighbours a...