Ok, Brian, before i have time to read the whole of that i would like to thank you for giving more time and thought into your answer than the bloody garage has!
On a good note i called them today, they are awaiting a call back from BMW but the head mechanic thinks (from the video) that it is the ignition coil playing up, so i would be happy if they just got on and replaced those, but i understand that it is an expensive and long job so as its under warranty they aint exactly enthralled by the idea that it is that. But i dont care, i want it fixed or i dont want it.