I liked this. The characters were quite likable, and the situations quite funny (a brothel with a granny Fetish, the brothel receptionist who is asked to play the role of angry wife, but gets in trouble for ad libbing an accent, and then for going into the wrong room and shouting down the wrong patron).
I heard that some people have criticized the program for the subject matter (be it prostitution in general (conceptually), prostitution in reality (and the problems of poverty, human traffic, and other atrocities), infidelity, criminal enterprises, etc. I don't really have a comment on that.
I think the show isn't about all that, and those serious issues can find a better forum. It is a comedy of manners. A far can you bend a respectable and posh British gent who is put in not so respectable situations?
The main character sounds unbelievably like a friend of mine, who is a university professor in Japan. That added to my own amusement.