hi
Do you have all the codes , ie engineers code? Without it you can't do it , you would have to default the panel and start again
I assume your in Ireland?
Can we external link here? I pm you just in case not
Although
https://www.securitywarehouse.co.uk/catalog/honeywell-ade-informa-speech-dialler-p-1425.html
Put it on a bench if it works then your problem is the cable or how your mounting it
If it doesn't work then maybe you shorted something on the bell
Rear switch is just another tamper switch if it has one , you will seen it unless it's the same switch which rests on wall and gets pushed down by the screws or lid on some boxes