25.—(1) An oil heater designed to be operated with an adjustable wick shall be so constructed that, if it is filled, lit, and adjusted as specified in Appendix C to the British Standard Specification of 1974, it shall not be possible by turning the wick down as far as it will go to cause the flame to ignite the fuel in the fuel container.
(2) The wick referred to in paragraph (1) above shall be a wick worn down to the lowest height which permits the heater to burn with a normal flame.