5.—(1) Where an increase in premium has been effected under regulation 4 the sum assured or guaranteed by the policy or contract under which the increased premium is payable shall be increased by an amount determined in accordance with rules which have been certified by an actuary to be fair in relation to the increased premium payable and have been approved by the Industrial Assurance Commissioner.
(2) Where the sum assured or guaranteed by a policy or contract is increased by virtue of the preceding paragraph the company or society shall on being requested in writing to do so by the person by whom the increased premium is payable notify him in writing of the amount of the increase in the sum assured or guaranteed.
6.—(1) Where an industrial assurance company or collecting society has adopted the prescribed scheme by a resolution making such provision as is referred to in regulation 4(1), the person insured under a policy or contract of a class specified in the provision which was issued or made before 6th April 1979 and under which the premium exceeds £4 every four weeks may before that date irrevocably elect, in the form set out in Schedule 2 to these Regulations or in a form to the like effect, that the premium under the contract under which he is insured shall be increased with effect from 6th April 1979 to such sum as is mentioned in regulation 4(1).
(2) Where such election has been made the increase in premium shall be effective as from 6th April 1979 as if it had been effected under regulation 4(2), and regulation 5 shall apply in respect of an increase in premium under this regulation as it applies in relation to an increase under regulation 4.