Where a person serving in a temporary capacity as a whole time officer of a local authority, being an authority specified in Part I of the First Schedule to the Local Government Superannuation Act, 1937, ceased so to serve in order to undertake war service and had then attained the age of eighteen years but was not then a contributory employee or a local Act contributor, and, if he had not ceased so to serve, he would have become a contributory employee or a local Act contributor on some date falling within the period of his war service, he shall be entitled to reckon so much of his war service as falls after the said date as contributing service or as service for the purposes of the local Act scheme, and section four of the Act shall have effect in respect of that part of his war service as if he had not ceased to serve as aforesaid in order to undertake war service until immediately after the said date.