Newcastle United remain in talks to break their transfer record this summer. That record currently belongs to Alexander Isak, who cost Newcastle United £63million two years ago. When he arrived from Real Sociedad, he became Newcastle’s most expensive signing ever. But Isak could be replaced at the top before the transfer window closes on August 30th, as Toon officials aim to complete a deal for Marc Guehi. The 24-year-old is the Magpies’ top centre-back target, but a deal is yet to be agreed with Crystal Palace. However, Guehi is keen to sign for Newcastle, and there is real hope that he will …