(UK) roundabout collision, 50/50 liability or all my fault?

hi! today I got into a road accident using a roundabout. i was in the outer lane and someone from the inner lane cut across me to reach an exit and hit my drivers side, causing a dent in my driver's side and my front headlights to pop out. I have dash cam footage too.

I was *almost* sure I was in the correct lane; i take this roundabout 5 days a week for work and never have had an issue + I follow what other people do on the roundabout and nearly everyone takes the lane i was in for this exit I was going towards. everyone around me seemed to be in agreement that I was okay to take this exit but when I posted it on reddit asking for clarification, I basically got called a moron who doesnt know how roundabouts work lol.

so I guess im at fault for being in the wrong lane. the guy that cut across me however, done so at an excessive speed and didnt indicate. where he cut into my lane, gave the impression to me like he was going to miss his exit because he seemed to turn quite late? like almost like he realised "oh shit that's my exit" and just swerved without looking or indicating and just going for it.

does this sound like a 50/50 liability case? or would it be my fault entirely for being in the wrong lane? orr despite being in the wrong lane, was him not checking his mirrors and not indicating and just going for it place more blame on him?

im kind of stressed about what the outcome of this situation would be ngl, im young and this person was very condescending to me upon getting out and sharing details with him which has been playing in my head all day because he spoke to me like I was a child despite being potentially the same age or younger than me? the car he drove was also quite 'fancy' which makes me worried for my insurance if im found entirely at fault 🙁