As someone who would LOVE to give gloryhole experiences, but doesn't have a suitable premises, I applied to work at the SW18 place. It's run/owned by a man (who's email replies were good English/not txtspk) who runs the profile and advertising and books whichever girls will be on the day's rota. He was happy to take me on as a large lady, and explained that he advertises on the profile which girls are working that day.
The things that put me off was 1) it's run by a man (if anyone's going to manage clients for me, I'd rather it be a woman who knows what it's like to suck random willies for cash) and 2) he took approx 30-40% of earnings (I can't do the maths!).
And finally 3) From what I can see, the SW18 place is a flat, one of the doorways has a sheet of MDF fixed up in it, with a hole big enough for the punter to pull out and look through at the girl. WHich to me, kinda cancels out the whole GH point - anonymous BJs and HJs to leave the rest to your imagination. I'd love to do anon BJs and HJs. So norty