Complex sentence: Prior to broadcasting TVS refused to take on most of Southerns series expect from the arrangement to cover two Glyndebourne operas each year, but with the advent of Channel 4 a year later the operas were shown on Channel 4.
Split into simpler sentences: Prior to broadcasting TVS refused to take on most of Southerns series except the arrangement to cover two Glyndebourne operas each year. With the advent of Channel 4 a year later the operas were shown on Channel 4.