Veterinary Medicine in the UK

you would be best contacting the unis direct as you don't seem to have as many GCSEs as a UK student would need. Some vet schools don't allow resits so don't apply to them. You would need an A in chemistry for most of the vet schools.
You would definitely need work experience before the application in October of yr 13.

What about resitting my GCSEs? would that also affect?

I don't know. There are only 11 (or 12?) vet schools in the UK. By looking at the websites for entry criteria you can take the ones that don't allow resits off the list (the Scottish ones?). For what is left you can email them for advice as your education is not UK standard. They will be able to tell you if they would consider you or if you should resit subjects.