Accenta 6 - severed wirimg to KeyPad. How to rewire?

Hi,

I have an Accenta 6 unit with a single Keypad (many years of fault-free opertion).

The wire connecting the main control unit to the Keypad was severed and the blue light won't turn off outside the house. Don't have exact details of how this happened - a scissors prank during a teenage house party!

I've had quotes of £200+ to fix this - but I wanted to ask for advice on the viability of doing this myself. I'm thinking I just get a new length of 6-core cable, switch off the mains, open the main control unit, wire the cable into both the main control unit and the keypad (matching the colours between the 6 marked terminals in both), close everything up ... and switch the mains back on.

But what happens next? Smiles all round? Alarm needs reprogramming? Alarm needs resetting? A big bang and fire?

I do still have the original installation manuals, factory set codes, my own code and a circuit diagram of the control unit.

Please can anyone advise? Is this something a non-prefessional can do?

Many thanks in advance,

JonKMale