Scantronic 9454 - tamp/fault/service?

Hi
Just moved into a new house and when electrician was installing a new consumer panel, he removed the fuse to the control box on the alarm.

We now have the user
code and manuals but the alarm is in day mode and shows tamp/fault/service lights.

Vendors told us battery needs replacing but other than that system works. Could old battery and removal of fuse causing this combination of lights and if so, is it something we can sort?

We know system is old but are planning on doing work to the house so would rather see if we can get a bit longer out of it and then upgrade or renew later.

Help appreciated.