fairy, we've been to Longleat and Elveden. Loved both. As dd is nearly four and probably pedalling around (?) Longleat is rather hilly, Elveden is much flatter for the cycling. There is a big boardwalk at Longleat that goes bottom to top, which is OK, but one of us was pushing big pram and the other sorting out moany 5 yr old!
We've done a straightforward villa and an executive villa. (you get cleaner in exec). This time we are going exec again, its a treat to have the cleaner (I think you can add it on to basic anyway). Bedrooms are a good size, fitted a cot next to our bed, didnt fall over it too much!
They have great playgrounds, our eldest (when he was 4 & 5) got SO into crazy golf! Crazy was the word.
It is all great really, book the activities when you get there, they do go pretty quick. Babysitters are very good, local, police checked etc. I think Rhiannon has used CenterParcs and babysitters lots too and gives them full marks.
We did a food shop before we entered CenterParc (me on an economy drive and not knowing how big or expensive the shop was) it's not too bad. But if you have your favourites take them with you.
Cant think what else really, just go for it, and then you can decide what worked best for you, for your next booking! CenterParcs doesnt tend to be a one-off!