The Scottish unis offer Veterinary Medicine only, which qualifies you as a vet. The other unis are the same except Bristol and Liverpool which call their degree "veterinary science" but still qualifies you as a vet. Apart from these two, all other "veterinary science" courses are science degrees only and do not qualify you as a vet. As for advanced Highers, the Scottish unis require two (biology and chemistry, BB) but most English unis require three, apart from RVC. If you are capable of three and want to apply to English vet schools, I'd say do them if you can.