14. With the exception of catalytic heating appliances, an appliance of the kind described in regulation 111(3)(b) or (c) which is fitted to a motor vehicle shall be fitted with a flue which shall be—
(a)connected to an outlet which is on the outside of the vehicle,
(b)constructed and located so as to prevent expelled matter from entering the vehicle, and
(c)located so that it will not cause adverse effect to, or suffer adverse effect from, the exhaust outlet of the engine or other source of heat.