Thanks for all your input. Just got around to reading them as for some reason I am not getting notified of replies, even though I am set up to do so.
Things have changed for me at the moment. My trusty MkII decided to snap the cam belt, so I have just got back home on the back of a truck.
Mechanic is giving me a ring tomorrow with a price to fix it.
In reply to the 1.5 dci in the newer cars, I did test drive one the other day and although it was adequate, it was not as lively as my 2.0 16v and was quite noisy. It had 31k on the clock.
I was particularly looking at 7 seater Scenics but was quite surprised at the lack of space in them. The car is slightly longer, but the back seats and the middle row are so close it would make for a very claustrophobic journey. Moving the middle row forward simply meant that both rows had little room. Very odd for a car actually designed as a 7 seater.
I also didn't like the electric parking brake. It was not as instant as yanking up a mechanical handbrake on a hill and made for at least one dodgy moment during my test drive!
Overall, I think adamh is right. Get a 2003 model, with less miles than mine and in better condition. That's once I've got the cambelt done of course.