Saloon boot not opening & side lights cause error

[GMGinger]

Hi,

I've recently bought a 55 plate Focus 1.6 Titanium 4 door Saloon (I take it that means it's a Mk2), no issues for the first month, but the boot release has started becoming troublesome. It suddenly became reluctant to open the boor - it would take ~20 attempts before the boot would release (same issue whether using key or switch on boot lid). I could hear a slight clicking noise from inside the lid each time, so it's trying to do something, but just failing to do it successfully. Today I've noticed too that when I switch the side lights on, it triggers the "luggage compartment open" error, even though the boot's securely down.

I've tried to read as many relevant posts as possible, but would like to check before buying and trying to replace something. I don't think it's water getting into the boot switch since the key fob release has the same issue (although I've not actually checked that it's dry). My next thought was that it's the boot lock mechanism that I need to replace, but now with the side lights triggering the luggage compartment warning, does this instead sound like the boot wiring loom needs replacing?

If the boot wiring loom does fit the symptoms, how big a job is it to replace?

Many thanks from a forum noobie.