I love using AirBnb to rent a house from a real person, but often come across properties which are listed on AirBnb by a professional rental agency. In this case you're charged whatever fee the agency is charging the owner, plus AirBnb's fee.
Within Australia it's often possible to find the identical house on a rival site such as Stayz.com for the same price, minus the AirBnb fee.
Is there a reputable alternative to AirBnb for short-term house rental in London, UK?