Gingerbreadman...what about renting a room in someone's house? My boyfriend's mum rents hers out (when he's not there I hasten to add!) and she lives in Christchurch. There are loads of people who do it too so you won't necessarily have the hassle of a contract, will py a reasonable amount for rent/keep and it's negotiable. You'd have full use of a kitchen with somewhere to store food if you needed to, although some places do tend to charge a little extra if you wish to use their washing/drying machine etc which is only fair.
If I had a 3 bed place I'd rent a room out to CATC students as I'm only in Christchurch myself. Try flatmateclick.com (or UK??) as they may have something, the noticeboards at the school and word of mouth from graduating students perhaps.
HTH