Judgment of the Court (Sixth Chamber) of 19 June 2003 in Case C-149/01 (Reference for a preliminary ruling from the Court of Appeal (England & Wales) (Civil Division): Commissioners of Customs & Excise v First Choice Holidays plc (Sixth VAT Directive — Article 26(2) — Special scheme for the taxation of travel agents and tour operators — Taxable amount — Margin — Total amount to be paid by the traveller)