The enlargement, improvement or other alteration, as often as the person having the right to carry out such operations may desire, of any such building as is mentioned in paragraph 1 of Part r of this Schedule, or any building substituted therefor by the carrying out of any such operations as are mentioned in that paragraph, so long as the cubic content of the original building is not increased or exceeded, in the case of a dwellinghouse, by more than one-tenth or seventeen hundred and fifty cubic feet, whichever is the greater, and in any other ,case by more than one-tenth.

The carrying out, on land which was used for the purposes of agriculture or forestry on the appointed day, of any building or other operations required for the purposes of that use, other than operations for the erection, enlargement, improvement or alteration of dwelling-houses or of buildings used for the purposes of market gardens, nursery grounds or timber yards or for other purposes not connected with general farming operations, or with the cultivation or felling of trees.

The winning and working, on land held or occupied with land used for the purposes of agriculture, of any minerals reasonably required for the purposes of that use, including the fertilisation of the land so used and the maintenance, improvement or alteration of buildings or works thereon which are occupied or used for the purposes aforesaid.

The winning and working of peat by any person for the domestic requirements of that person.

In the case of a building or other land which, on the appointed day, was used for a purpose falling within any general class specified in an order made by the Secretary of State for the purposes of this paragraph, or which, being unoccupied on the appointed day, was last used (otherwise than before the seventh day of January, nineteen hundred and thirty-seven) for any such purpose, the use of that building or land for any other purpose falling within the same general class.

In the case of any building or other land which, on the appointed day, was in the occupation of a person by whom it was used as to part only for a particular purpose, the use for that purpose of any additional part of the building or land not exceeding one-tenth of the cubic content of the part of the building used for that purpose on the appointed day or, as the case may be, one-tenth of the area of the land so used on that day.

The deposit of waste materials or refuse in connection with the working of minerals on any land comprised, in a site which, on the appointed day, was being used for that purpose, so far as may be reasonably required in connection with the working of those minerals.