LONDON - Since Tesco Clubcard re-launched in May a million more customers have signed up for the loyalty card at a rate of six every minute.Clubcard Double Points launched in August - giving customers twopoints for every £1 they spend on anything in store or online.Tesco claims that more people in the UK now have a Tesco Clubcard loyalty card than own a Barclaycard, the nation’s biggest credit card.Tesco now has 16 million active Clubcard holders in the UK, compared to 11.7 million people who have a Barclaycard.Tesco has....