The Local Authorities' Cemeteries Order 1977

1.  The powers described in article 16(2) shall not be exercisable—

(a) contrary to the terms of the agreement, in respect of any grave, vault, tombstone or other memorial which the burial authority are bound by agreement to maintain;

(b) within the period of the grant or of any extension thereof, in respect of any tombstone or other memorial placed in the cemetery in pursuance of a grant made after the coming into operation of this order;

(c) within the period of the grant or of any extension thereof, except where a reservation as to the exercise of powers under any local enactment was made on the making of the grant, in respect of any tombstone or other memorial placed in the cemetery in pursuance of a grant made under the order of 1974;

(d) in respect of any other tombstone or other memorial placed in the cemetery (otherwise than under a permission expressed to be revocable) within the 20 years preceding the first publication of the notice required by paragraph 3,

except with the consent in writing of the person entitled to the benefit of the agreement to maintain, the owner of the right to place and maintain the tombstone or other memorial or the person granted permission to place the tombstone or other memorial.