Punters piled in on gossip that the entrepreneur, whose private company builds flats across London and the Docklands, had agreed to buy the 20m shares from leisure magnate Trevor Hemmings, Arena's largest shareholder with 40%. The mystery buyer apparently wants to get involved in next year's planned redevelopment of Royal Windsor racecourse. Buying a stake in the company would not be a bad start and would give him bargaining power.