Our toilet has been getting progressively hard to flush, to the extent that the toilet handle has now cracked. Therefore I was going to try and remove the syphon element to replace the flapper plasticy bit at the bottom (apologies for the technical terms here!). Anyway we have a Dudley Turbo 88 system so easy peasy I thought, don't need to remove all the bits etc just the syphon bit - that bits ok but I don't have enough room for it to lift out as the handle is in the way - so I unscrewed the large nut on here but it won't come off as the lever is preventing it from doing so and I'm not sure how the lever bit should come off, I've tried with reasonable force to twist/pull it, but with no look. Picture attached which hopefully shows my problem - can anybody advise how to remove the lever (the short-ish white plastic bit). Many thanks.