Do you mean Haggerston Castle?
If you do, we hated it. Sorry. I found it tacky and expensive. You have to go through the amusement arcade to get to the playpark/swimming pool. Ok, if you are good at resisting, "Mummy, want a go on that".
The pool was nothing special. We did not go to the restaurants.
Saying that, I have friends who have been several times and loved it so maybe it was just us. We went with Tesco vouchers so it was reasonably priced, I would have been annoyed if I had paid full price.
The area itself is great. Great beaches, we were at Bamburgh. The castle there is nice too.
A great place to go, though very expensive is Alnwick Castle and Gardens. (Hogwarts in the films) Take a picnic and spend the whole day there. Great for DCs.
The Honey Farm is great too.
How old are your DCs?
I would go again to the area.