E.3—(1) For the purposes of Class E—
“significant extension” or “significant alteration” means any extension or alteration, as the case may be, of the building where the cubic content of the original building would be exceeded by more than 10% or the height of the building as extended or altered would exceed the height of the original building; and
“site notice” means a notice containing—
the name of the applicant,
the address or location of the proposed development,
a description of the proposed development and of the materials to be used,
a statement that the prior approval of the authority will be required as to the siting, design and external appearance of the building or, as the case may be, the siting and means of construction of the private way,
the name and address of the local planning authority,
and which is signed and dated by or on behalf of the applicant.
(2) For the purposes of Class E, development that is reasonably necessary for the purposes of forestry includes works for the erection, extension or alteration of a building for housing a biomass boiler or an anaerobic digestion system; for storage of fuel for or waste from that boiler or system; or for housing a hydro-turbine.