Erection of a private garage or carport within the curtilage of a dwelling
A garage or car port measuring up to 6m by 6m and with an eaves level not exceeding 2.9m may be erected without planning permission providing all the conditions set down in Class 17 (Page 17) of the Permitted Development Order are satisfied. (See link below)
Those conditions are:
For a full copy of the Order click this link. Class 17, page 17 refers.
Where there is an existing garage which is part of or attached to the dwelling the garage space may be used as additional living accommodation and/or part of the main house without the need to apply for planning permission.
Planning permission is not required to replace a garage door with a window provided that the new window matches those existing in the ground floor on the same elevation AND that there is sufficient space elsewhere within the residential curtilage to accommodate two full sized car parking spaces (full sized parking spaces are 3.25m by 6m).