Complex sentence: The club then moved to the Spartan League, and finished top of the league, however they were denied the championship, as it was discovered the club had played an ineligible player so they finished third when six points were deducted.
Split into simpler sentences: The club then moved to the Spartan League, and finished top of the league. However, they were denied the championship, as it was discovered the club had played an ineligible player, so they finished third when six points were deducted.