Went here with my grandsons (2 and 8). Was delighted to find that the childrens' zoo was free. It had everything from reindeer and llamas to chickens and fish. We particularly liked watching the mother sow feed her piglets.
About 5-10 mins away through the park is an excellent childrens' playground with a wide variety of every type of climbing frame etc, suitable for toddlers to teens.
There is also apparently a paddling pool open in the summer which we did not investigate on our December visit.
Parking is easy and free for 2 hours at weekend (otherwise 95p).
We shall certainly be returning as it is good to have fun with grandchildren without having to pay – and there is a pub in the park if we should decide to stay for lunch!