Having lurked inthis forum yesterday, I found out enough about my failing
sensor to go and replace it this morning!
Guess What - all my "failing to start intermittantly for 5 minutes" starting problems now seem to have vanished! All for £21.21
I have taken some photos to help others in the same boat!
They are hosted by tinypics, and are here:
(new one and packaging)
(Position in engine bay of Megane 2.0
(closer view of above)
Thanks to all for your help,
and HAPPY NEW YEAR!