18. Any admission agreement made, or having effect as if made, under section 15 of the Local Government Superannuation Act 1953 section 7 of the Superannuation (Miscellaneous Provisions) Act 1948 or any corresponding local Act provision, whereby the employees of any body are, or can be, admitted to participate in the benefits of the superannuation fund maintained by any authority mentioned in column (1) of schedule 1 shall have effect in all respects as an agreement on the like terms and conditions between such body or, if that body ceases to exist on 1st April 1965, the body succeeding to its functions, and the authority set opposite such first mentioned authority in column (2) of that schedule, and in the case of an agreement made under a local Act provision, as if it had been made under the said section 15 with the approval of the Minister.