33.—(1) Subject to paragraph (3), before a billing authority applies for a liability order it shall serve on the person against whom the application is to be made a notice (“final notice”), which is to be in addition to any notice required to be served under Part V, and which is to state every amount in respect of which the authority is to make the application.
(2) A final notice may be served in respect of an amount at any time after it has become due.
(3) A final notice need not be served on a person who has been served under regulation 23(1) with a reminder notice in respect of the amount concerned.