Complex sentence: The club had reached the same level in 2011, following five promotions in six seasons; however they were relegated from the Conference South at the end of the 2012--13 season after going into administration.
Split into simpler sentences: The club had reached the same level in 2011, following five promotions in six seasons. However, they were relegated from the Conference South at the end of the 2012--13 season after going into administration.