It hasnt grown at all this year, ive watered and gave it feed, whats wrong with it?
I know nothing of cordylines but that looks like a lot of root/stem for the size of the pot.
Your right again Nut.I have loads that i have been grwing from seed for several years now which are planted in pots and boarders,.Yours ogster is definately root bound.Repot it, giving it a couple of inches all around the pot use a good quality peat free compost mixed with grit for added drainage.
I agree with Diddy, it definitely needs re-potting.
It may be worth trying to seperate one of the smaller shoots at the base when repotting,to give yourself another plant.
when is the best time to do this?
That doesn't look like a Cordyline to me, looks like a variegated Yukka. I'd refresh in same pot, breaking some corms off to re-plant, and most of the others I'd throw, just leave some base to the growing bits. Put all in a mix of multi- purpose and grit, water in and leave in cold GH until spring.