I got someone else to use my save and go to that area, it worked fine for them. It worked for me too once they sent the save game back. Then when I leave and try to return, it crashes again.
I'm sure the logs will provide the answer as to why.
It's probably also worth noting that I went to Cliaban Rilag last night and it was fine, I don't understand what changed. I hadn't used this save since April so perhaps something is screwing it up with the updates that were applied in that time.