By Tom Gott Manchester United are working to complete a deal for 16-year-old Arsenal striker Chido Martin Obi, reports have revealed. Martin Obi broke Arsenal’s Under-18 goalscoring record last season with an incredible tally of 32 goals in just 18 games, with 28 of those goals coming in just nine matches at the end of the season. His schoolboy contract expired this summer and Arsenal made an offer to tie Martin Obi down to a scholarship deal, but the teenager has turned down the chance to extend at the Emirates and is heading for pastures new. As first revealed by AcademyScoop, and later back…