File photo dated 05/07/18 of police at the home of Charlie Rowley, 45, in Muggleton Road in Amesbury, Wiltshire, who, along with his partner Dawn Sturgess, 44, was exposed to the deadly nerve agent Novichok last month. Experts are trying to determine whether the Novichok that poisoned a couple in Wiltshire was from the same batch used in the attempted murder of Sergei Skripal and his daughter Yulia, after the nerve agent was found in a small bottle at Mr Rowley's home.