H.1 Development is not permitted by Class H if—
(a)the gross floor space of any new building erected would exceed—
(i)for a building on article 2(3) land or on a site of special scientific interest, 100 square metres;
(ii)in any other case, would exceed 200 square metres;
(b)the gross floor space of the original building would be exceeded by more than—
(i)in respect of an original building or a development on article 2(3) land, 10% or 500 square metres (whichever is lesser);
(ii)in respect of an original building or a development on a site of special scientific interest, 25% or 1,000 square metres (whichever is the lesser);
(iii)in any other case, 50% or 1,000 square metres (whichever is the lesser);
(c)the height of any part of the new building erected would exceed—
(i)if within 10 metres of a boundary of the curtilage of the premises, 5 metres;
(ii)in all other cases, the height of the highest building within the curtilage of the premises or 15 metres, whichever is lower;
(d)the height of the building as extended or altered would exceed—
(i)if within 10 metres of a boundary of the curtilage of the premises, 5 metres;
(ii)in all other cases, the height of the building being extended or altered;
(e)any part of the development would be within 5 metres of any boundary of the curtilage of the premises;
(f)the development would lead to a reduction in the space available for the parking or turning of vehicles; or
(g)the development would be within the curtilage of a listed building.