Complex sentence: At first the debut show began with 5 million viewers at 10.30pm, but by the end of the 45-minute show, the audience had halved to 2.5 million, fewer than the 3.3 million watching "Notting Hill" on Channel 4 between 11pm and 11:15pm.
Split into simpler sentences: At first the debut show began with 5 million viewers at 10.30pm. But by the end of the 45-minute show, the audience had halved to 2.5 million, fewer than the 3.3 million watching "Notting Hill" on Channel 4 between 11pm and 11:15pm.