Progress, of sorts..... using the second video above (thanks Alpha Omega) and the purchased tools, I successfully, eventually, gained access to the rear of the MMI. The cables are very short and a couple have to be unclipped to get to the back. Plugged in a generic GPS aerial off ebay (less the £5.00!!) and it all started working, 9/10 satellies received... happy me .. or so I thought...... I couldn't work out/see any way to mount the aerial near the windscreen, so simply placed it on top of the MMI. Then had some "fun" getting it all back together..... there is VERY little room and the numerous cables conspire to prevent easy access/movement ... but got there eventually. Test drove it and it was VERY erratic, quick check and only 3/4 satellites... so obviously on top of the MMI is useless. Another days work I guess trying to find a better place/way, but at least I know how to gain access.
To add to my woes, the "safety systems" warning is now illuminated... I wonder if the repeated moving of the seat and kneeling on it to try and get a torch/eyesight into the MMI area has damaged something, a very quick look doesn't show any loose connections, again something for another day ...
......at 72 my arthiritus, bad back, eyesight and patience have all run short for today !