Where a person has travelled from a place in the area of one local health authority to a hospital in the area of another local health authority for the purpose of attending at, or being accommodated in, that hospital in order to avail himself of any hospital or specialist services and, immediately after such attendance or on the termination of the period of his accommodation in the hospital (not being a period longer than three months beginning with the date of his admission to the hospital), he is conveyed by ambulance or other means of transport made available by the local health authority for the area in which the hospital is situated, in pursuance of their duty under section twenty-seven of the Act of 1946, from that hospital to the place from which he travelled as aforesaid or to any other place in the area of the local health authority within which the first-mentioned place is situated, the cost of that conveyance shall be repaid by the last-mentioned authority to the local health authority by whom the ambulance or other means of transport was made available as aforesaid:
Provided that any local health authority may agree to waive their rights under this section against any other local health authority, either in consideration of a periodical payment or without consideration.