Paragraph 9A F1

the gross floor space of the original building would be exceeded by more than—

whichever is the lesser;

the height of the building as extended or altered would exceed 4 metres;

any part of the development, other than an alteration, would be within 10 metres of any boundary of the curtilage of the premises;

the development would result in a reduction in the space available for the parking or turning of vehicles;

the development would consist of or include the construction or provision of a veranda, balcony or raised platform;

any part of the development would alter or extend beyond an existing shop or financial or professional services establishment front; F2...

the building as extended or altered is to be used for purposes other than that of the shop or financial or professional services establishment concerned;

it would be development described in class 7A(1).

a site of archaeological interest;

a national scenic area;

a historic garden or designed landscape;

a historic battlefield;

a conservation area;

a National Park; or

a World Heritage Site.

the erection of any additional building within the curtilage of another building, whether by virtue of this class or other use, and used in connection with it is to be treated as the extension of that building, and the additional building is not to be treated as an original building;

where two or more original buildings are within the same curtilage and are used for the same undertaking, they are to be treated as a single original building in making any measurement.