I doubt you’ll get any hint there.
And posting any action u just might get has proven to be a great way to have these places shut down.
If the massage is being down in a flat, and only places they advertise is gum tree, or viva street, it probably unlikely to draw the attention of the council or police, however
If the place where the massage is being done, is a shop, and have a website, you could class this place as a legitimate place, where massage is offered and nothing else