Harry Styles marked his 30th birthday by cold water swimming. The former One Direction singer, who celebrated the milestone age on Thursday (01.02.24), is renowned for his gruelling fitness regimes and was photographed leaving Hampstead Heath pond in London with friends. Harry was seen wrapped up in a black tracksuit, mac, baseball cap and glasses after the freezing dip, and carried a £85 tote bag over his shoulder as he left the spot with two male pals. He’s previously been spotted taking a dip in the lake with his actress girlfriend Taylor Russell, 29, who he’s been dating since at least Aug…