Complex sentence: After missing out on the title on the last day for the previous two seasons, Leinster finally won the 2007--08 title with one game remaining, however they had been runaway leaders for much of the season.
Split into simpler sentences: After missing out on the title on the last day for the previous two seasons, Leinster finally won the 2007--08 title with one game remaining. They had been runaway leaders for much of the season.