um, yeah, what that bloke said. normally i would recommend staying well away from cheap diamond sharpeners. they can be unevenly graded and put some big scoremarks on your blades. break them in with an old beater knife that you don't mind scratching up. when you've knocked all the big lumps off of the stone you can progress to normal knives. i got mine in B&Q too.
still wouldn't put any of my better knives on it, but it's good for reprofiling.
It sharpened mine, its not pretty but its sharpened
Not got a lot of experience with knife sharpening so practising with a couple of Moras. I have also nearly got a decent edge on my machete with it, got to go down a couple of grits tomorrow, I was knackered after re-profiling it though.