After breaking and remaking a cable how can I reset the Veritas 8c?

I recently moved house the Veritas 8c worked fine. After the builders separated two pieced cables one using 4 cores one with 6 core to remove a cupboard, the alarm went off. After lots of panic the connections were remade and the alarm code put in and it silenced. I have not been able to reset the alarm since. I have done a 'cold reset' and it recognises the default code but does not active the system. The battery seems fine as it powers the system without the mains.

When I put in the default code the three red lights corresponding to the three zones come on and the unset light stops flashing when I press full. Inputting the code again turns them off. But no exit signal or alarm.

I seem to remember that the motion sensors used to flash.

I'd be grateful for any help.

Many thanks