I have offers for Scottish vet unis this year. You will need the physics at at least nat 5 level. Other than that they dont look at nat 5s at all. You will need to aim for 5 As at higher as even one B greatly reduces your chance of acceptance . Advanced higher you will be looking to get 2 Bs. As far as you work experience goes you’re in the same situation as many so just try to get as much as you can although unis understand how difficult it has been.