So, yeah, I did mean an asian massage parlour, and if anyone wants to tell me how to change that in the threat title then I will.
Just come back so I thought I'd add my 2 cents, based on what I experienced and the other advice given.
My girl did offer b2b and HR, so it was that kind of place. There was indeed a shower in the room but, also, things like baby wipes and (interestingly) toothpaste - not the sorts of things you'd expect in a strictly legitimate massage place, so I'd see that as possibly another indication of what to expect when you go in.
The girl came in wearing a fairly professional masseuse uniform, but that came off at the right time - so outfit doesn't always appear to be a good tell. I was buck naked, and no embarrassment on her part. In fact, before we started, I noticed her taking a sneaky glance, so that was another good sign. I had the towel just next to me, so if I'd got it wrong, she could've covered me up. I was told to "strip and lie on the bed", so if I'd completely misjudged, that would have been the excuse.
No CC swipes or subtle touches until after the question around services, but that might be because I told her it was my first time.
The funny thing is that the place I went to seems to run a legitimate operation as well - the HEs seem like an extra bit on the side for the girls. Throughout my massage, I was listening to the yelps of a woman in a room on the floor above having a round of acupuncture and, later, cupping. It wasn't offputting, and the girl just passed it off with a laugh, but it was a bit surreal.
Anyway, thanks for all the helpful advice - definitely helped. If the title gets changed, perhaps this'll be useful information for others in the same position.