It's a very grey area. I remember I saw a Czech WG. in Stirling, and when I entered the flat she said said ahhh the other 'girls' are in there. So technically that was a brothel?
Also I remember when I started punting and discovered this site, I found a girl from Escort Scotland. I went to the flat in Partick and I thought it was a bait and switch. She then asked me if if I wanted a 2 on 1 with the other girl which cost me another 60 quid for half an hour. The girl (Brazilian ) I believe came in and I realized it was her from the photo on the website. So technically that is a brothel too.
The facts are -
1) 2 or more girls working from the same premises at the same time
2) 2 or more girls working from the same premises at different times ( which includes the escort agencies that send the girls to the same flats )
That's why I highlighted indigo and more recently Roxa ( Polish ) in my reviews and comments.
Granted , these premises are surely way down the pecking order as far as the local vice squads are concerned. ( Although who knows what polish Roxa's pimp is also into , or wether she is entrepreneur of the year and self employed. )? I don't know.
Bottom line is that meeting a girl , one on one , in a hotel room , rented flat , or her own flat , is not illegal.
It's clear that these flats were moving higher volumes of EE skanks thorough the premises that even the inbred job dodging neds that populate that area will notice what's going on.
That is why I prefer hotels and apartments that you know are one on one meets.
Incidentally , a WG once told me that she had a client that worked in vice / drugs. I know , the irony.
And they know about all the flats that are brothels. But, if they ain't causing any trouble, or ain't run by foreigners, they are left alone. It's only when known criminals are behind them, then they are targeted.