Complex sentence: Darlington went into administration in 2004, in 2009, and again in October 2011 when enough money was raised by fans groups to compete for the whole of the 2011--12 season, which ended with Darlington relegated into the Conference North.
Split into simpler sentences: Darlington went into administration in 2004, in 2009, and again in October 2011. On this third occasion, enough money was raised by fans groups to compete for the whole of the 2011--12 season, which ended with Darlington relegated into the Conference North.