Thank-you jokiin and kamkar1. Ordered my camera from Amazon Friday evening (fulfilled by Amazon, supplier Hiniko) it arrived at my local collection point in under 24 hours, so by Saturday tea-time I was the proud possessor of a S/G 9663 DC and hard-wire gizmo.
Experienced/tech savvy readers won't be interested in my progress, but just in case a newbee such as myself is reading this thread, here is my first progress (?) report. It may prevent some time wasting :
Before going down the 'install' route, I've been out this afternoon (Monday) and done a link-up of cameras and, using the cigarette-lighter power-lead, made sure I'd not got a Friday afternoon kit. All was well, except (being a tech numpty) I spent about 3/4 of an hour trying to access 'stand-by' mode so I could explore the 'menu' functions, and tweek those appropriate to my needs. The on-line user-guide doesn't specifically mention how to access this state of affairs and in my experimenting I took numerous pictures of my knee/steering wheel/gearlever etc when pressing the <Menu> button (stop laughing at the back there !). I eventually found the answer of course. The secret was discovered in the guide under <Rec> Key, Function 1: Video recording. As any experienced readers will already know, all I had to do was, having started my car and the camera initiated in live, I just had to give the <Rec> key a prod and the recording function was turned off and the camera was in 'standby', and I could access the <Menu>, rather than photo my knee again. It's amazing how some of us oldies can make a mountain out of a molehill isn't it !!!
Tiredness and failing light then stopped play. My next task is to see if I can poke a long,thin, robust wand of wood down under the head lining (at a slight angle across the centre-line of the car) from the tailgate end to the rear view mirror area so I can attach the rear camera lead and drag it back under the lining to the back of the car. Taking cues from jokiin and kamkar1, I've temp. fixed the shorter of the two camera leads to the rearview mirror and pulled the lead fairly taught to see how much lead is available for threading thro' the rubber tube concertina wiring protector leading from car bodywork across the tailgate hinge void and into the tailgate itself. From my little experiment, there may not be quite enough length in the 3 metre lead for that last little wriggle, but from how tight the head-lining is to the roof itself, I may be forced to use the long lead and go the long way round and tuck oodles of spare cable inside the head-lining. Pity a 4 metre cable isn't available.
Well, I'm indoors in the warm now, I've had some tea and now going to create another frustrating experience downloading/opening/hopefully installing zip-file contents with the pc viewer software. If I manage it (3:1 against) I'll see if there is anything on my memory card. The camera was beeping quite a lot at me as I finished my in-car shenanigans. Oh for the days of chalk and slate, coke cans and string !!!