Complex sentence: Plough Lane continued to be used by both Wimbledon and Crystal Palace as the home ground for their reserve teams' home matches until 1998, when Sam Hammam sold the ground to Safeway.
Split into simpler sentences: Plough Lane continued to be used by both Wimbledon and Crystal Palace as the home ground for their reserve teams' home matches. This was the case until 1998, when Sam Hammam sold the ground to Safeway.