Make sure the wire 'octagonal-type-thing' holder is nicely in place, if it's loose, gently stretch it out a little to give it more 'spring' against the inside of the bezel.
Then firmly push down flat & turn the bezel (doesn't matter which way) into place, if there is too much resistance, the wire spring may have popped out of place.

Stewart

: thanks for that, ive just used your guide to dismantle teh
: watch...but one more question how do i get the bezel back on...