Where an insured person, not having been entitled to injury benefit in respect of a relevant disease, claims disablement benefit in respect of that disease, and in accordance with Chapter 3 of Part 4 of these Regulations, a date of development is determined for the purposes of that claim, the following shall apply -

(a) Section 75(3) (which relates to the period for which disablement benefit is not available) shall not apply and the claim shall be treated as if there had been no injury benefit period,

(b) Section 75(6) (which relates to the period to be taken into account by an assessment of the extent of the claimant's disablement) shall have effect as if for references therein to the end of the injury benefit period were substituted by references to the date of development.