Pyronix Sterling 10 alarm

Hi everyone, i am Jenny - i am new to this forum and hoping for some help.
Recently moved to a new house and have the Sterling 10 alarm fitted. The problem is we dont have the alarm code and seen as the past owner is now in Prison, i have no chance of getting it lol.
The main display panel is blank, but it has power to it - presuming the main battery has gone, but dont dare try and replace it in case the tamper alarm goes off and i dont have the code. Rang local alram company and they are wanting to charge £90 to just come and look at it! Oh plus VAT!! Grrr.
Is there some kind of engineer master code to re-set the system? HELP appreciated.

Jen

open the case and kill power from mains and remove the battery back up should stop it going off for too long
then get the ref numbers off the main board and google it . most can be reset via jumper or hard reset button