Well, I have the next bit (temporarily) sorted now.
Won an auction on ebay last night for a 6.5" Pioneer screen, brand-new, £81 :D Picked it up this morning as the company selling it is just around the corner from where i'm working, so bit of a result there.
The plan now is to install the HKS Camp, and then plug it into this screen i've got. All going well and it works, i'll then remove my satnav screen and replace it with this one. I've got a mate whose an electronics wizard and he's going to look at my satnav unit with some kind of scope, apparently picks up the outputs and stuff, and he reckons we can knock up an adaptor.
I will keep you updated :)