Sutton Garden are happy to advise and help you negotiate through any planning issues that may arise, below are the basic rules and guidelines:
Rules governing outbuildings apply to sheds, greenhouses and garages as well as other ancillary garden buildings such as swimming pools, ponds, sauna cabins, kennels, enclosures (including tennis courts) and many other kinds of structure for a purpose incidental to the enjoyment of the dwelling house.
Outbuildings are considered to be permitted development, not needing planning permission, subject to the following limits and conditions: