Yes saw one in Walsall many years ago.
Popped into see one of the ladies who worked there. While I was waiting I got talking to the mature maid. She said she worked there to help her daughter out as it was a her new place. In the end the lady was free and ended up having a good service. I asked the maid on the way out if she worked, she said ring her later.
Spoke to her and she said no as it's her daughters place and couldn't do it. Eventually I went back to the place and saw the daughter who was working. On the way out the maid the mom offered me a drink and we got talking. I asked her again if she would see me at anytime, she to my amazement agreed. We agreed to meet after the parlour had closed and on a week her daughter was off.
Met the lady and she said she only ever slept with her husband