Finance director John Coombes is appointed interim managing director with effect from September 1 until a replacement can be found.
In a letter to FSG members, Callery says: “It is with much regret that I will be leaving FSG, particularly at such an exciting time with all the success we are enjoying with the development of the trading groups.
“However, from my own point of view the opportunity to go into a new business is one that I feel is right for both my family and myself.”
Tom Keeping, managing director of FSG parent company Alliance Automotive, says the split was amicable. “David and his team have achieved a great deal for members,” he says.