Clifford Concept 600 here. It was fitted about 10 years ago as far as I remember (I have the original paperwork at home).
I have had a few 'false' alarms, but it's due to the proximity sensor being set too sensitive at the moment - my master fob broke so I have no way of turning it down until I get a new one - and trees/petals etc will set it off.
It is an excellent alarm system though
