Just a heads up to anyone considering going here. We went last Wednesday en route further South and it was incredibly disappointing. We used Tesco vouchers to get in which softened the blow somewhat but I was still really annoyed and unimpressed with the place. The queues to get in were ridiculous; we at least got the faster queue in as we had the vouchers (the fast line also works for pre-booked tickets). Even so, I reckon we waited half an hour to get in. This is because they insist you do the factory "tour" - ie, they herd about 30 of you into an enclosed space whilst a staff member pretends to be a mad professor and you spend 5 minutes learning how lego is made.
The rest of the place is a glorified soft play but much more expensive to get into.
They were charging £4.25 for a kid's lunch box which, if I remember correctly contained a fruit shoot, small ham or cheese roll, packet of crisps and a bit of fruit.
The best bit was the 4D cinema; it was very good.
The place is much smaller with much less to do than the map would have you think. It was mobbed when we were there and it's safe to say we didn't enjoy it, I think it would have cost about £40 for 2 kids and 2 adults to get in.
The shop was also really disappointing - my kids were really keen to buy some Toy Story 3 lego but all they had were the £20, 30 and £50 sets - no little individual figures or any pocket money stuff. I spoke to a staff member to see if they had any more stock and he basically just shrugged and said that's all they had.
I left a really unhappy online questionnaire and really hope that they contact me to discuss it. I just feel that it's a bit of a rip off, especially compared to Legoland Windsor.
Hope this helps someone!