How to set the Alarm for an ADE Accenta 8 mini without a valid code?

After the alarm was without mains or battery power for a time the system will not recognise my code. I have followed the user manual to try to operate the system to no avail. Is there a special code used to reset the system and if so where can I find it? Any help please! I can't afford £70 for an engineer to press a few buttons!!!