Hi, Jess,
The courses at the UK veterinary schools qualify you, legally at least, to treat any animal species.
After graduating you can then try to get a job working in the area of your special interest, but I think that it is a good idea to have a spell in general mixed practice first so as to consolidate what you have learned.
It might be a good idea too to get some experience of working with zoo animasl - working at Hewletts, for example, which is in Kent and should be accessible to you. They will have a vet who might allow you to 'see practice' once you have started on the course.
W.