I have inherited a house with a Bentley Symphony 2 alarm. there is no engineers manual. How can I reset code?

The alarm is active, but I don't know the the code. The house belongs to my late father-in-law. I know it is not protocol to give this information over the net, but I'm willing to produce evidence to confirm my request. Anyone willing to help ?|||talk to www.alarmassist.com|||Count of 1?