Okay guys, after a very sleepless night, firstly a big thank you to Pauly and Absolut5 for their help last night.
It does looks like I must have drilled through the cable when putting the shelf up, too much of a coincidence for the camera to stop working after fitting units at the weekend.
I Took the shelf unit down this morning first light, hoping that after removal of the screws I may have got the camera signal back as Absolut5 mentioned but no luck there, on unscrewing the screw nearest the Drivers B pillar it did feel and sound like I had screwed into something but I cant be certain.
So, more help please:
My understanding is its only the coaxial cable which runs down the drivers side not the power cable, so no fuse? my miss understanding. What about the cable down the B pillar to isolate the internal alarm sensors? does this go to the front and down the A windscreen pillar, not checked this yet?
Will take Pauly's advise tonight and test the power connection at the back of the camera in the tailgate to check for a permanent negative, live and switched live when selecting reverse.
Will then attempt to get the head unit out to test the coaxial cable at both ends for continuity, never attempted this before will need to get some advice on how to do this first.
I understand the camera connection is called a "fakra" connection. Can I simply buy a roll of coaxial cable route it through as best I can and simply connect one of these into the camera connection:
https://www.reichelt.com/gb/en/fakra-c-buchse-25-mm-lang-zum-crimpen-delock-89687-p236072.html?CTYPE=0&MWSTFREE=0&PROVID=2788&gclid=CjwKCAjw-OHkBRBkEiwAoOZql_pA3eb0CFRYKkEqJSCF-3DDaHKYyhD8xub7KIFjOO_MJs3PR903VhoCoskQAvD_BwE&&r=1
Or can I somehow cut and join the cable at the tailgate?
Any help on wheres best to run the cable (damage limitation) Skyline roof fitted, van all carpeted.
On a positive note I won't need to take the van into VW at the moment, was dreading that.
Will post pics up as I go along, but could really really do with your help please guys!