If I were Hannah I'd consider getting a lameness workup after just watching the vlog. It's a very extreme reaction for seasons, even when she's not in season, she's not massively different. In the comments she says a physio has never recommended a lameness work up. But they're not a vet, some might be good at spotting lameness but they're not there for that. If you think your pony needs a full MOT, then have a full MOT, with a vet!
Having watched the vlog, I even more think they want to do different things and it'd be better for both when Hannah realises that.
I'd also agree, why did she go onto the cross country phase, not sure I'd even continue my show jump round if it was like, would of been better off popping number 1 again and retiring. She doesn't look quite right behind to me. She's wanting to do these things and not miss out, which I understand but the horse has come to first and it's becoming clear the pony physically and mentally not suitable for what Hannah wants to do.