Within ten days of the first lockdown in March 2020, fintech veteran Oli Cavanagh had an idea. He was ordering take-out pints, meals and coffees around his home in Blackrock in south Dublin but realised he could no longer tip the staff or delivery drivers serving him. A serial entrepreneur who has founded or worked in nine different fintech start-ups, Cavanagh could feel his brain begin to buzz as he tried to think of a solution to tipping when no one was using cash. He rang up Charles Dowd, a payments expert who had previously worked in Facebook in Menlo…