manual for gardtec 800?

Hi,
I also have moved into a house recently that is fitted wit a Secure Alarms LCD keypad and a box upstairs labelled GARDTEC 800 series. The box has a square panel on the RHS. How do I get the panel off? At the moment, the alarm is not energised. Can anyone tell me where I can get a manual to find out exactly how to use it? I also have a number that seems to activate/deactivate the alarm. Does it have a battery installed somewhere and how do I check its charge-state?
Any information at all would be helpful.