In a nutshell, the rent paid to Brentford FC was causing the club to slowly bleed to death. In addition the club had to compensate the residents in the cramped streets around Griffin Park every time SKY turned up with their equipment because of the inconvienience.
The deal from Harlequins RU was a three year rent free tenure at The Stoop on the proviso that the club adopted the name and colours of the Union team.(this did not extend to a share of matchday catering) If the club proved to be successful at the end of the three years the Union club would consider merging with the League club if it proved to be a financially viable entity in its own right that would not drain funds from the Union club.
In 2008 The Union club board declined the option to purchase the League club. Since then the League club has paid a "commercial rent" for the use of the Stoop. This is also one undisclosed reason why only one or two stads are ever open - cost reduction as the whole ground does not have to be stewarded. In addition to the request from SKY to concentrate the spectators.