http://www.legislation.gov.uk/ssi/2020/437/article/13The Town and Country Planning (General Permitted Development and Use Classes) (Scotland) Amendment Order 2020texttext/xmlenTOWN AND COUNTRY PLANNINGStatute Law Database2024-09-19Expert Participation2021-04-01 This Order amends the Town and Country Planning (General Permitted Development) (Scotland) Order 1992 (“the 1992 Order”) to introduce new classes of permitted development rights and makes a minor amendment to the Town and Country Planning (Use Classes) (Scotland) Order 1997. 13In Part 6 of schedule 1, in the interpretation section—aafter the definition of “building” insert—“designated area” means—aa national scenic area,ba National Parkca World Heritage Site,da historic garden or designed landscape,ethe curtilage of a category A listed building,fa site of archaeological interest,ga conservation area,,bfor the definition of “significant extension” and “significant alteration” substitute—“significant extension” and “significant alteration” mean—ain respect of the period before 1 April 2021, any extension or alteration 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,bin respect of the period beginning on 1 April 2021, any extension or alteration of the building where the cubic content of the original building would be exceeded by more than 20% or the height of the building as extended or altered would exceed the height of the original building,,cafter the definition of “slurry” insert—“World Heritage Site” means land appearing on the World Heritage List kept under article 11(2) of the 1972 UNESCO Convention for the Protection of the World Cultural and Natural Heritage..Art. 13 in force at 1.4.2021, see art. 1