I have just become the proud owner of a lovely cappo for the second time after a 28 year gap. Happily my joints are still flexible enough for me to use it

I would like to check out the wiring/function of the fitted radio and alarm/immobiliser, but I am not able to do this myself proficiently, so I'm looking to get an auto-electrician to give the car a once over.
Before I stick a pin in the local ads for one, I was wondering if anyone has a recommendation? I'm based in Dorset, but prepared to travel a reasonable distance (up to 100miles) for someone who has experience of working on cappos and won't fleece me.
Cheers,
Steve
PS. The alarm (a Laserline 984) has its fobs, but hasn't been used. I'm reluctant to try switching it on, unless it works but can't be shut down. The radio is a Sony CDX-M8800 with a remote, but does not work. I also have a loose switch on the glovebox attached to a blue wire and a white wire, which I have been brave enough to activate, but can't see what effect it has.