Complex sentence: In 2001 they were relegated into Division 2 after 25 years, missing promotion in 2002 but rose again into Division 1 at the end of the 2002--03 season after finishing second place.
Split into simpler sentences: In 2001 they were relegated into Division 2 after 25 years. They did not manage to gain an immediate promotion back in the following season, but achieved a return to Division 1 at the end of the 2002--03 season after finishing in second place.