ALWAYS get tensioners. They're usually what fail and take your cam belt, and then valves with them. For the sake of a few quid you're looking at hundreds i.e. over £1200 of engine rebuild. Don't be an idiot - get the whole job done. Probably worth getting the water pump changed too or it's likely to fail requiring the cam belt job to be done all over again.
FAST of Stockton-upon-Tees do cambelt and water pump and tensioners for £245.