A.1—(1) Development is not permitted by Class A(a) if—E+W
(a)in the case of the installation of apparatus (other than on a building or other structure) the apparatus, excluding any antenna, would exceed a height of 15 metres above ground level;
(b)in the case of the alteration or replacement of apparatus already installed (other than on a building or other structure), the apparatus, excluding any antenna, would when altered or replaced exceed the height of the existing apparatus or a height of 15 metres above ground level, whichever is the greater; or
(c)in the case of the alteration or replacement of an existing mast (other than on a building or other structure, on article 2(3) land or on any land which is, or is within, a site of special scientific interest)—
(i)the mast, excluding any antenna, would when altered or replaced—
(aa)exceed a height of 20 metres above ground level;
(bb)at any given height exceed the width of the existing mast at the same height by more than one third; or
(ii)where antenna support structures are altered or replaced, the combined width of the mast and any antenna support structures would exceed the combined width of the existing mast and any antenna support structures by more than one third.