Regulation 123 of the Principal Regulations is amended as follows:(a) by omitting from subregulation (1) "trailer" first occurring and substituting "light trailer" ;(b) by omitting from subregulation (1) "motor vehicle" and substituting "light motor vehicle" ;(c) by omitting subregulation (2) and substituting the following subregulation:(2) However, subregulation (1) does not apply to a light trailer with a GTM over 2 tonnes built before 1 July 1991.(d) by omitting from subregulation (3) "trailer" first occurring and substituting "light trailer" .