Welcome to the site. Thanks for sharing your videos. It would be interesting to see a few hitting videos.
Regarding defense/catching - I want to give you honest feedback, positive and negative...
You have some interesting physical tools and a good build but catching mechanics are still raw and very much a work in progress. I like your quick release and decent athleticism. But most of your throws, you spin off/fall off too much. Your feet are reasonably quick but they are often going in the wrong direction. Your framing is pretty good but your blocking too often finishes falling forward and lacks balance/control. You don't quite work around the ball enough. American colleges, generally, will want catchers that are closer to being ready to contribute and not as much of a project with skill set advancement. I love that you show so much poise and patience in dealing with less than ideal support help in putting together the videos. You show the right demeanor. I think, with much work between now and summer, you can give them something to see at the showcases but it will take a lot more work. Most good HS catchers who will go on to play at the college level spend some time with a good catching instructor. At this point, you do not project as a D1 catcher defensively. I suspect that will be too big of a gap to realistically make up. But lower level colleges aren't out of the question with some focused work efforts.
Another challenge, I'm guessing, will be your preparedness in regards to facing good pitching as a hitter. Like I said, it would be great to see some hitting videos. You will need to figure out a way to find challenging pitching to face before coming over and showcasing if you haven't already. Again, colleges want to take players who have a history of success against good competition and just polish them a bit... not build a player up from the ground floor. And hitting is a very big piece of the equation they will be looking at.
You mentioned you use youtube for self-teaching... have you used the "catching 101 with Xan Barksdale" youtube clips? The catcher in those instructionals is a very good example to emulate.
A lot of coaches here would love to work with someone like you to see if they could get you college-ready. I would think there are some resources somewhere in the London area. Is that an option?