23 Effects of becoming subject to liability under, or entitled to benefit of, covenant etc.E+W
(1)Where as a result of an assignment a person becomes, by virtue of this Act, bound by or entitled to the benefit of a covenant, he shall not by virtue of this Act have any liability or rights under the covenant in relation to any time falling before the assignment.
(2)Subsection (1) does not preclude any such rights being expressly assigned to the person in question.
(3)Where as a result of an assignment a person becomes, by virtue of this Act, entitled to a right of re-entry contained in a tenancy, that right shall be exercisable in relation to any breach of a covenant of the tenancy occurring before the assignment as in relation to one occurring thereafter, unless by reason of any waiver or release it was not so exercisable immediately before the assignment.