It's tough, every new year you'll fight a new batch of students alongside reapplicants. I never knew this was possible, but my friend told me a person in his course (dentistry) applied to med as his 5th choice and got an interview. Think he just did it for the hell of it and was surprised as well. No clue about all this blacklisting thing, but I do know some unis only let you apply so many times eg. Belfast you can only apply twice and has another restriction about having to apply to them first time you apply to med or they'll reject (can't really remember, but I had to email them my UCAS documents from when I applied to medicine as proof I wasn't applying to medicine back then) and Aberdeen only lets you apply 3 times then your application will get blocked. Shouldn't be a problem for OP as it sounds like he's from year 6?
I got an offer from the last uni I wanted to go, was a bit sad since I didn't want to move there but I got in so I was ecstatic. Got another offer but I would take anything they give me. I ruined my application cycle due to having an off day and bombed the UKCAT despite scoring avg/above avg marks. Luckily this cycle was my good day and got a good mark. I hate this damn test, it'll be a gamble that you can acheive the same or a better UKCAT! And you never know how the interview will go and how you feel that day and how aggressive the interviewer may be. I would suggest you try out what people have suggested and visit the uni, try and arrange a tour or something with the uni (some do this!) and go to offer holders day if you still can and speak to people and visit the place. I found leaving home for my undergrad very daunting and tbh my first year went horrible (suffered from some depression) but after getting through first year, I got back on my feet and found it a blast and thoroughly enjoyed my time there! Just remember there are people out there who keep applying and get in after their 5th or more attempts!
I hope my personal input would give you some food for thought in your decision.