Veritas 8c?

Hi,
My friends recently bought a house which was a repossesion and there is a Veritas 8c alarm fitted which they have been unable to use as no code or manual was given with the house. Is there a way to reset to a default code if so grateful if anyone could advise how, as don't want to tamper and ahve the alarm going off and not being able to stop it!
Does anyone know how much a service / engineer check of the system would be also on average?
Thanks
Gav