Apparently they are to be called 'micro brothels'.
There can be, like Tealeaf said, up to three prostitutes (male or female,) working from the same premises.
They can apparently also employ a 'maid'. This is were they will come unstuck. If they advertise at the local job centre, they will have to advertise for a male, or female maid, otherwise they will be breaking the law regarding sex discrimination.
