15.—(1) A person may not count any period of membership if his contributions for that period have been returned to him.
(2) A person may not count any period of membership if his rights in respect of it have been transferred by payment of a transfer value (see Part 9).
(3) A person may not count as a period of membership for the purpose of calculating any benefit under regulations 16 to 20 or 29 to 31 of the Benefits Regulations so much of his membership as requires to be excluded to reduce the value referred to in regulation 74 (2) (b) of these Regulations by the amount recovered or retained under regulation 74 (recovery or retention where former member has misconduct obligation).
(4) Where a person pays contributions under regulation 20 (trade disputes) for any period, that period counts as a period within regulation 6 of the Benefits Regulations even if his contract of employment did not subsist throughout that period.
(5) A period of membership under regulation 6(1)(a) of the Benefits Regulations includes any period for which a member is treated as having paid contributions under regulations 17 (concurrent employments) or 46(4) (rights to return of contributions).