I haven't read the whole thread, so this may have been mentioned.
When you add alarms and trackers etc if you declare these to your insurer it's highly likely they
won't pay out if your van goes AWOL broken into etc if the security device wasn't operating or fitted at the time
the incident occurred. Sometimes it can be the preferable not to declare the security fitment, especially
if they only knock a few quid off the premium anyway.
I don't declare security measures on my M/bikes for this reason, but best to enquire of individual insurers
they have their little idiosyncrasies in the small print if you know what I mean?