I was able to use a tesco £10 off voucher on my first order. I have tried using more vouchers but they were all denied apart from a £5 off.
I came accross an ebay auction, where a guy was actually selling these vouchers even though they are easily found for free. Anyway he stated he would explain how you can get around using the codes even if you are a current customer.
How is this done, i hope its not just opening a new account because I only have the one debit card. Could changing your email address be the answer.