Went during 1/2 term break and agree that a family ticket is quite expensive...however we visited twice in the week and really got good value out of it.
Worth checking to see if there are any special events on, when we went the second time there was a theatre company doing shows and mask making which the children loved.
The zoo itself is quite small, don't overestimate the time you will spend here, but for younger ones a good 1/2 day trip - plenty of things at lower levels for them to see and interaction with the animals available.
Would really recommend the cafe! Really good food for a very reasonable price, especially childrens meals - which in all honesty could have fed an adult for lunch.
TOP TIP: Look at the junior keeper experiences for two kids! - When discounted it is a very reasonable offer for what is included.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.