Networker (Menvier) TS690R

I have a 16 years old TS690R alarm that was disarmed by an engineer when I had all windows and doors replaced, thus removing all contact pads. I thought the system was disconnected but when the electricity trips, because of a storm for example, the external sounder goes off and light flashes. I have tried taking the battery out of the control panel and fuse out of the box above the panel but this doesn't stop it. Is there a back up battery in the external unit? Most power cuts seem to be in the middle of the night and I can not do anything to silence the alarm. It only stops when the power comes back on! Can anyone help please?

Yes there is a battery in the external unit. Th panel supplies a signal to the external box to STOP the box from sounding. If that signal is removed, as happens with a power cut, then the box will sound on it's internal battery. The reaon for doing it this way is so that if the wires to the external unit are cut in an attempt to disable the alarm then the alarm will sound..

So in other words .... A ....get ladders out and disconnect battery in bell box....or
B.... Replace control panel battery back up this keeps system running in a power cut

Thank you Bernardgreen and Sparkymarka. I will get the ladder out tomorrow (it's raining now!). will the bell sound when I remove the external bell cover? If so I'll wear ear defenders. There is no point in replacing the internal battery as I guess it will need replacing every 4 years or so.

update to removing the battery in the external box:
Got up the ladder and opened up the cover only to find what looked like two capacitors, no battery. The alarm blaring (I had ear plugs in!) there was no option other than ripping out the wires. The alarm is now defunct. I have removed the panel from the wall and the whole kit is destined for the recycling graveyard. RIP TS690R, or at least I will now!