5. Any certificate given for the purposes of sub-paragraph (1)(c) of paragraph 4 of Schedule 1A to the Act before the date of coming into force of these Regulations to a person who, immediately before that date, was exempt from liability to pay the personal community charge and the personal community water charge under the said paragraph 4 shall continue to have effect for those purposes notwithstanding the substitution of another definition of severely mentally impaired by regulation 4 above.