Dear Hayley,
To the best of my knowledge, though I may be a little out of date, your daughter would be best afvised to go for A levels in Chemisty, Biology and Physics/maths. aiming for an A or A* in each.
Work with animals, in a livery stables, on a farm, in a boarding kennel is very useful experience as would be voluntary work in your local veterinary practice.
There are six veterinary schools in the UK, and the course takes 5 years at Liverpool ( your nearest) Bristol, London, Nottigham, Glasgow and Edinburgh and 6 years at Cambridge.
You can get a good deal of background knowledge about the veterinary profession on: www.rcvs.org.uk.
W