A.2 Development is permitted by Class A subject to the following conditions—
(a)any alteration is at ground floor level only;
(b)any extension is, in the case of article 2(3) land, constructed using materials which have a similar external appearance to those used for the building being extended; and
(c)any extension or alteration is only to be used as part of, or for a purpose incidental to, the use of the shop or financial or professional services establishment.