In this Schedule—
(1) a name marked (a) refers to the substance for which it is the common name currently recommended by the British Standards Institution at the date on which these regulations are made;
(2) a name marked (b) refers to the substance for which it is the chemical name;
(3) a name marked (c) refers to the substance which is generally known by this name;
(4) alternative names refer to the same substance; and
(5) a reference to a chemical substance which is not a salt or an ester includes separate references to each of its salts and esters.