Hi not sure if you have fixed it yet? Mine started doing the same last week, the problem is that the alarm has a service timer feature, the beeping means that it is ready for a service. This feature will have been set by the last engineer so he gets repeat business. This can be bypassed by following the steps ( prog 9999730 reset reset reset)
The feature is not required as the factory setting would not use this feature.
It worked for me anyway!
Matt
January 2012