Definitely keep Mattock - he's improved a bit and has been one of our least-worst defenders... so far

Potter is unlikley to be fit enough to play again in the first team before his contract runs out... so no

Most of the others (except Bray and probably Onariase) could be ok in League 1, if we get relegated, but probably not if we manage to stay up.
Can't see Warney wanting Dom Ball back though