Where a person had been entitled to invalidity allowance or transitional invalidity allowance at any time during a period of 57 days before attaining pensionable age, sections 4737 (increase of Category A retirement pension for invalidity) and 6138 (exclusion of increase of benefit for failure to satisfy contribution condition) shall continue to have effect as though Article 13 of, and paragraph 13 of Schedule 1 to, the Order had not come into operation and as though any reference to invalidity allowance in section 47 were a reference to transitional invalidity allowance or invalidity allowance.