I haven't been in the same situation but I would say the best starting point would be to email and/or ring the universities you are interested in (or all of them) to tell them about your situation and ask for their advice. As far as I know only Notts, Liverpool, RVC and Bristol consider resit students so if you're definitely planning to resit Chem they're probably the places you'll want to contact first. It's not unheard of for people to drop out of their degree to pursue Vet Med so they should be able to tell you if they'd be able to consider your application as normal.
You have good grades though and if you get that extra work experience and boost your Chemistry grade I personally think you stand a decent chance of getting in, though obviously I've no idea how the unis view people who've dropped out to change courses which is why I think you should definitely contact them to ask before you make any decisions!