Hallo Brian, long time since I've seen you posting. It is indeed the IDM intruder alarm, should be a booklet with it but if it's missing I'm sure there are many members that would be willing to email you a copy. Just got rid of our Bailey together with all the literature so can't help.
To be honest, never bothered setting ours cos the alarm was so pathetic you'd have to be standing within a couple of yards of the van to hear it. Should be a little charger with it as well cos it has it's own battery under the seat by the fuse panel. Charger like a mobile phone and the jack plug goes into the key pad.......Mick