What would you do in this situation?

I think the question of whether it was taken seriously by the police would depend, in part, on where it happened.

Beyond that, I went through an internal argument with myself on what advice to give you. It went like this:

  1. Did you feel safe in his home?
  2. Do you think he would do this to others?
  3. WTF difference does it make whether he would do this to others? it’s bad enough that he did it to you.
  4. Reporting sexual assault to the police might be time consuming and annoying. True - but this is probably going to be a battery complaint, which makes things a lot less involved than a rape complaint.
  5. It’s been a while. Will that make it less likely that they believe her? OTOH, she did talk to Airbnb right away.

I circled on this, IOW.

Here’s where I net out. Yes, this was sexual assault. I believe that the police would take this seriously here in the US, particularly given the circumstances that gave him access to women alone in his home on a regular basis. If you don’t mind making the phone call to the local police, I would imagine the worst thing that would happen is that you’ll waste a few hours answering questions.

Curious, what do you see as the safety difference between an “actual B&B” and airbnb?

Certainly in the UK a standard B&B is normally someone’s house that they decided to rent rooms out of, but without any kind of central complaints office, and possibly without any real review system.

OK, so I have pretty broad safety standards, I have hitchhiked, couchsurfed with strangers and generally travel solo, so maybe I’m missing something, but I really don’t get it…

This happened in the UK.

I have the impression that the UK authorities would take this seriously.

First of all I’m sorry you got harassed. Since you’re in the UK, call the police.

Secondly renting a room only gets you to meet one local (and as you found, they may be unpleasant and then it’s hard to get away from them.)
Next time I’d book into a hotel instead and ask reception about local activities that interest you.