Buy now, pay later firms like Klarna and Block's Afterpay could be about to face tougher rules in the U.K.Nikolas Kokovlis | Nurphoto | Getty ImagesLONDON — More startups are being spun out of Swedish digital payments firm Klarna than any other financial technology unicorn in Europe, according to a new report from venture capital firm Accel.Accel's "Fintech Founder Factory" report shows that alumni from Klarna have gone on to create a total of 62 new startups, including the likes of Swedish lend...