Plates, sheets, film, foil and strip, of non-cellular poly‘ethylene terephthalate’, not reinforced, laminated, supported or similarly combined with other materials, without backing, unworked or merely surface-worked or merely cut into squares or rectangle (excl. those of poly‘methyl methacrylate’, self-adhesive products, and floor, wall and ceiling coverings of heading 3918) 25 18 15 12 9 9