Why can I not book a single from Calais using my vouchers? As a UK based promotion this is the agreement with Tesco. Related articles How do I book with Tesco Clubcard vouchers? How do I check-in if I have booked using Tesco vouchers? What happens if I arrive early or late? Do I get change if I send in too many vouchers What about people only travelling from Calais to Folkestone?