Former France defender, William Gallas, has said he is yet to be fully convinced by Mikel Arteta’s plan for Kai Havertz, despite his impressive run of form. Havertz arrived from Chelsea in the summer in a £65million deal. The German initially struggled to justify the big transfer fee and win over his new fans. However, Havertz has gradually begun to establish himself as a key member of the Gunners’ squad. Despite now having scored seven goals in all competitions, Gallas has not been bought over. He told Lord Ping: “Even though he’s scored in his last few games, I’m not convinced he’ll have a g…