By Keith Weir LONDON (Reuters) - Insurer Aon will sponsor Manchester United's training kit and have its name attached to the club's training ground under a new eight-year agreement announced on Monday. The commercial appeal of the Premier League giants means they can do separate sponsorship deals for their training kit and the famous red shirts they play in. It is the first time United have sold naming rights to their training ground in Carrington on the outskirts of Manchester in northern England.