Complex sentence: The stadium closed on 31 December 1975 until further notice but reopened during March 1976 and eventually found a buyer in 1977 when Northern Sports purchased the track for £250,000.
Split into simpler sentences: The stadium closed on 31 December 1975 until further notice. It reopened during March 1976 and eventually found a buyer in 1977 when Northern Sports purchased the track for £250,000.