5Where a person who is in war service immediately before the end of the present emergency continues in the same service after the end thereof, the said service continued as aforesaid shall all be treated as war service for the purposes of the Act :
Provided that, except where the said person continues his war service in pursuance of a legal obligation so to do arising otherwise than by reason of a voluntary undertaking by him to continue it, the local authority by whom he was employed immediately before he undertook his war service may at any time by notice in writing given to him notify him that his war service for the purposes of the Act will be deemed to cease three months after the date of the service of the notice, and unless the authority withdraw their notice the said war service shall be deemed to cease accordingly.