Ok, so after all the help from this forum, I've just put a deposit on a 05 plate scenic. I managed to find a clean one with full history and warranty - all as recommended. Thank you all for your words. Just a couple of points for anyone else going through the same debate - research always helps, but before you take the information to heart, have a look at the scoring system. One major pole places the scenic in 74th place out of 113 makes and models, however the difference in the score between the best MPV and the Scenic is only 3%, further more, the difference between the Scenic and the next best MPV's is a range of 0.1% - 0.7%. So unless I'm really unlucky, the margin is very slim and not worth the extra initial £2500.
So, here's to plenty of happy motoring miles - something that's been missing for the last year with the current car.