191Meaning of “established use”
For the purposes of this Part a use of land is established if—
(a)it was begun before the beginning of 1964 without planning permission and has continued since the end of 1963;
(b)it was begun before the beginning of 1964 under a planning permission granted subject to conditions or limitations, which either have never been complied with or have not been complied with since the end of 1963; or
(c)it was begun after the end of 1963 as the result of a change of use not requiring planning permission and there has been, since the end of 1963, no change of use requiring planning permission.