Regulation 8
A person who owns or possesses any road vehicle constructed or adapted to use gas as fuel for its propulsion shall, if the Commissioners so require, keep books and documents showing in respect of each such vehicle—
the description, registration mark and number of the vehicle;
the date, quantity and description of all gas taken into the vehicle as fuel for its propulsion;
the date of, and the distance travelled by the vehicle on, each journey or where the vehicle is used otherwise than in making a journey from place to place, the date and nature of such use,
and shall retain such books and documents for not less than 12 months from the date of the last entry therein, and produce them on demand to an authorised person at all reasonable times for his inspection.