Thanks for your replies above.
After a lot of thought I've decided to just contact the installer and see how much they will charge to sort this out, I might even get them to recommission the system for us at the same time. We don't use it at the moment mostly because we have cats in the house...
So currently decorating a bedroom in our house, the wiring centre for the intruder alarm is in the built in cupboard in this bedroom and the wiring has all (rather poorly in my opinion) been run under the carpet and then at a hap hazard angle to the alarm control centre. (See pics)...