Having replaced the siphon on a close coupled wc, the doughnut was totally distorted. The problem is that the “universal” type you get from the likes of b&q are to thick, so the cistern sits to high and naturally when you flush (because the end of the siphon only goes into the pan a few mm) more water ends up on the floor than in the pan. Any ideas where I can get a thinner doughnut?