The law on maiding and brothels

Definition of a brothel
Any premises - for example, private flats, saunas, massage parlours - may be classified as a brothel if they are used by more than one man or woman for the purpose of prostitution, whether on the same day or on different days.
So, if you share premises with someone else and work on alternate days or weeks the premises will still count as a brothel, even though there is never more than one person working at any one time.
Where rooms or flats on one building are let separately to different individuals offering sexual services, the premises as a whole may still count as a brothel if the individuals are effectively working together.  Evidence of shared keys, washing and toilet facilities, staircases, tennancy agreements etc will still be relavent.
If you are the only person who provides sexual services on premises, with or without the assistance of a non working maid, the premises is not a brothel. (Release 'Sex Workers and the Law' 2011)

Although it is legal to have a maid or housekeeper to assist you and increase your safety, the police may allege that the maid is selling sex and that the premises therefore counts as a brothel, especially if she/he is young.
They may claim that a person has to be over a certain age in order to be a maid, this is not true, although it is a separate offence to allow a child between 4-15 years old to frequent a brothel.
Maids or housekeepers in brothels are clearly at risk of being accused of keeping a brothel.  However, if your duties are of a menial nature and you have no control over prices or services, general you will not be committing an offence.
When working with a lone sex woker, it may assist your defence if you have a clear written agreement on what your duties are (eg cleaning and raising the alarm of an assault by a customer).  (Release 'Sex Workers and the Law' 2011)