By Lars Mucklejohn The City watchdog has imposed restrictions on a fintech firm owned by Uruguay’s first-ever billionaires as it tries to improve standards in a more lightly regulated segment of the payments industry. The Financial Conduct Authority (FCA) has blocked Larstal Ltd, which operates as Astropay, from providing payment services, accepting new customer funds, or onboarding new customers without its written approval, according to a post on the FCA’s website from Tuesday. The FCA imposed the restrictions via a so-called voluntary undertaking, where a firm pledges to improve its operati…