As above, there isn’t a way into becoming a vet except having a vet degree. But the graduate entry I’ll warn about as an option because it is even more competitive to get in, obviously longer and much more expensive - I’m not as clued up on the Scottish student finance but I think (correct me if wrong someone) that you don’t get tuition fee funding for a second degree. Now I don’t know how that works if you went to a Scottish uni but I think if you went to an English one (as it is very competitive so I wouldn’t place bets on getting into a Scottish one 100%) that means you’d have to pay it yourself, and paying 9.25k a year is quite a lot, particularly as it can be difficult to work properly throughout the degree as it is busy - not impossible, many people do it, but it is part time and/or through holidays between placements so it is limited what you can earn too. But obviously it is an option many people do every year, so not discouraging but something to bear in mind.
Personally the better option would be to just resit them. If you applied in a cycle and got offers you didn’t meet, I’d be calling them up and seeing what options are possible - e.g. in very rare cases possibly a not oversubscribed course would accept maybe a grade below, particularly Nottingham April cohort which has in previous years gone into clearing. To follow from that I’d also make sure to be on top of checking clearing on results day, it is rare that there are spots and they get taken up very quickly, but you don’t know if you don’t try. But the unis may also carry over the offer as a deferred one if you wanted to resit - now this is also very rare and I’ve only heard of this happening during covid with CAG mess etc, but again, don’t know if you don’t try. But even if the calling up fails, I’d recommend resitting. It is just one year, I’d say maybe half of all my year group doesn’t come from the traditional school straight into uni route. You avoid all the expense, it’s shorter, you may be able to work through while you resit and earn savings, or do some other things, gap years are amazing even if you didn’t plan on it and seem daunting initially. While you resit you can reapply with prospective grades. Only thing to watch out for is some unis may have a “minimum” for your first attempt or they may stipulate higher requirements for resitting by a grade or two but that’s a uni by uni thing.