Orientation in advance is important
Novelty of location and resources can be a very motivating factor of visits, but in a totally unfamiliar setting people spend a lot of time familiarising themselves and this can lead to anxiety and lost opportunities, especially in younger pupils.
The more you can involve your students in planning the visit and their enquiry the better. Spend some time together looking at the maps provided, the website and the our introduction to Whipsnade Zoo. The visitor information page will be useful to look at just before your visit when it will have information about the day of your visit.
When you arrive at the zoo you might pause at the gate and help the students to locate themselves on the map.
Near the gate there is a toilet block (might be worth a visit...), refreshment outlets and the main gift shop - all places that groups might wish to visit at some point during the day. It is not far from here to the First Aid post: this is marked on maps and fingerposts around the zoo and you might take a moment to point this out. Take the students to the fingerpost near the main gate and talk to them about how to use it to find their way.