By Laura McGuire A record 93.4 per cent of all in-store card transactions up to £100 were made using contactless, according to a new study by Barclays, as the payment method traditionally used by youngsters goes mainstream. Shoppers made an average of 231 purchases spending £15.69 on average at a time. This is up 3.9 per cent on last year’s reading. Overall, this added up to shoppers spending £3,623 in total when using contactless payments. While this payment method, which links customers’ bank accounts to their smartphone or watch, is still more popular with young consumers, the gap between o…