I think I drew that in pain according the modified date it was 2014. That rift certainly is the crux of the cave, also quite scary getting into the darn thing. It's what stopped my first trip there when I was solo as I wanted to someone to pull me out lol.
I haven't made it past it. I got to the corner after much effort but couldn't turn around to carry on. Stood there for a while then posted back through. Going back was much less drama
The first part was the tightest bit if I recall, once you are stood in that corner, it should be a little easier to get through the next bit, but maybe I am remembering it wrong.
Yeah, I couldn't work out how to spin round in the corner. I might not have been trying my hardest because I wasn't looking forward to the return though.