I can't advise fully as I am a vet med student and know little about the vet nursing routes etc but why not discuss these queries with a vet nurse at your practice? No harm done if you phrase it as just a potential idea you were thinking about, they'll know a lot about it and also know you personally so they may be able to advise what route they think is best for you. They may also be able to answer questions re whether you are likely to be employed again after becoming an RVN and whether they may be able to drop you down to part time hours during your time as a student. Even though they may not be actively looking for someone part time, they may make exceptions and allow you do your placements there or work alongside your education as you are now which would help get extra money and practice. You won't know if you don't ask, this all seems like a very reasonable conversation to me and shouldn't anger anyone (and if it does, perhaps it isn't the best practice environment anyway).
I personally have seen the college route advised over the uni route due to being able to avoid student finance fees etc and it's perhaps a little more flexible - it only 1 day a week you are asking for to be in college which is not an unreasonable request imo. But re the student loans you said, I would do a little more research on that as that isn't exactly how student finance works. As long as you are eligible (more complex if international etc essentially), student finance pays your tuition fee (9.25k/year) automatically and also gives you a maintenance loan yearly that is normally based on your parents' income with about 4/4.5k being minimum. You only begin to pay these back once graduated, AND earning over a certain threshold - there's some new student finance rules from this year that honestly I'm not clued up on so the threshold may not be the same but it used to be ~25k/year before you start paying back. When you pay back, it is only a certain % based off the money over that threshold (i.e. you don't pay any of the 25k), again I think the rules on how much the % is now (was 9% I believe) but essentially it isn't a lot of money monthly that you are paying back, it is more in the margins of paying for a subscription/car insurance or whatever rather than 'paying back debts' like it is with a usual bank loan. It will get wiped off completely after (now) 40 years whether or not you've paid it back - and no one realistically pays it back because the interest on it is like crazy, and there is no benefits to paying it back apart from getting rid of the monthly charge. The only thing to bear in mind is that this only applies to the first degree you study, so if after you did a vet nursing degree you decided to do another degree you'd have to pay the tuition fee out of pocket (but still can get a mainteance loan). So I would do a little more research and asking around before making the jump, but overall I think you have many options available.