Looking back in recent season's the cub that wins promotion seems to stay up for two seasons with ChCh United the only team to be up and down in the same season as was in 2015, before that:
Nomads relegated in 2014, were promoted 2013 - finished 7th
FC Twenty11 relegated in 2013, were promoted in 2012 - finished 7th
ChCh United relegated in 2012, were promoted in 2009 - finished 6th, 5th in 2010 and 7th in 2011
Universities promoted in 2014 finished 7th and then 5th in 2015 and currently 6th.
With Halswell and Western currently to two bottomed placed sides their placing have been:
Halswell: 2015 7th, 2014 6th, 2013 5th, 2012 5th
Western: 2015 6th, 2014 2nd, 2013 4th, 2012 6th