My toilet has been difficult to flush recently. Now won't flush. The name on top of the flush valve is Derwent Macdee

William Kincaid, July 2009

Sounds like the diaphragm has got a split in it, and will need to be replaced.

you can buy them from any plumming center, and are not expensive to buy.

Although it can be a fiddly job getting on the floor and undoing the nuts , they always seem to be in hard to reach places, so give yourself a good hour or so for the job.

Michael Smith, July 2009

diaphragms gone in the syphon.

hi-spec plumbing & heating (essex), July 2009