Had a long trip yesterday, phone paired perfectly on the way as usual. On the way back, the phone symbol flashed on the car display but it wouldn't pair. At first stop tried by re-starting phone, phone Bluetooth, and car, in a variety of combinations. Nyet - no connection. Next stop 2 hours later (it was a very long trip), deleted all pairings on Myway, searched for phone, no phones found but the phone symbol still flashing in a lunatic manner. Spent another hour in crawling M25 traffic, thinking what's changed since this morning, then it dawned on my that the laptop in the back foot well under my coat was on standby, in the morning it had been shutdown. The laptop has Bluetooth enabled. By now off the M25, so pulled into a layby, shut down laptop, Normality restored, phone paired. I guess the car was in a lunatic loop trying to pair with a non-phone.
So, logical fault finding says to me car wont pair with phone, fault is car or phone. I had got to the point of thinking that I would have to reinstall firmware on one or the other when I got home. But - it was neither.
The only reason for posting this is to alert others who might one day have a similar oddity - if Bluetooth won't pair ask yourself if there is any other Bluetooth around that's confusing things. Wish I'd though of that first .....