Again the Ringer by Edgar Wallace — Read

There was a man who had an office in Chancery Lane, who described himself as The Exsome Domestic Agency. His ostensible business was the placing of domestic servants in new situations, and he specialised in that type of servant who had reason for not applying to his or her late employer for the indispensable "character".

He did not advertise this fact, either in the newspapers or on his nice note-heading, but it was pretty well known that he would supply necessary credentials for a consideration.