I did the 7 day course with the bicycle academy. It was really great, the guys are super nice, i left with a frame and so much learnt. Couldn't recommend them enough. They are based in Frome, Somerset. Not too bad to get to, cute little town, air bnb wasn't crazy expensive, there's even a masonic hall if you're into that kinda thing.
I think all the courses are always only 2 students to atleast 1/2 people teaching. I did mine with a really nice guy called Rory who had travelled all the way from New York state to do the course. A couple weeks ago i was thinking about contacting him to see how his frame came out. But i forgot his surname...bummer.
They have a nice setup where andrew or someone else cooked lunch each day, everyone sat and ate together. BTR fabrications are based in the same building. Listening to them discuss the details of framebuilding and other engineering/fab work really demonstrated the vast array of knowledge and skill available to us.
They have a very "modern" approach to teaching. There's no mystery framebuilding magic that can only be learnt with 10 years of framebuilding. Robin Mather did most of the teaching on the course i did, with a bit from Andrew the founder. Both are great teachers and I quickly became confident with the fillet brazing technique.
Overall really awesome, highlight of my year. Highly highly recommend