A provisional declaration made in accordance with paragraph 14 shall, as from the date on which the transfer election in question takes effect, take effect as if it had been made on that date pursuant to regulation 40(2):

Provided that if a regular police officer who has made a provisional declaration in accordance with paragraph 14 does not make a transfer election within the period of 3 months mentioned in paragraph 1(a) (or such longer period as the police authority may allow under paragraph 1) the provisional declaration shall cease to have effect as from the end of that period.