James you will struggle to find an insurer who is interested in whether you have a CAT1 alarm fitted or not. Most just want to hear you have an imobiliser. For example I called Tesco and Elephant, probably the 2 most popular insurance companies for people within ClioSPort, and asked how much discount they would offer me if I had a Cat 1 alarm fitted, Tracker and security film fitted to the windows (i was bored).
Total reduction = £5.
Griff