10. Briteflame briquettes, manufactured by Maxibrite Limited at Mwyndy Industrial Estate, Llantrisant, Rhondda Cynon Taf, which—
(a)comprise bituminous coal (as to approximately 10 to 15% of the total weight), petroleum coke (as to approximately 10 to 15% of the total weight), anthracite duff (as to approximately 70 to 80% of the total weight), and starch binder (as to the remaining weight);
(b)were manufactured from those constituents by a process involving roll-pressing and heat treatment at about 260°C;
(c)are unmarked pillow-shaped briquettes;
(d)have an average weight of 140 grams; and
(e)have a sulphur content not exceeding 1.9% sulphur on a dry basis.