Hi.i have fluid master flush system in our toilet fitted with single lever.last few days lever doesn't return after flushing. Have to raise it up gently and it would hold the position and Teddy to flushing. Have to repeat every time.so decided to replace it with new and dual flush handle.toilet handle always in 2 parts.handle stays outside and connected inside bo nut.this new unit lever couldn't loosen the nut.instructions clearly say it needs to come off but in vain.i purchased it from screwfix. I took it back and they swapped the handle with another one.when I asked them to to unscrew the the nut they didn't know how to.i have tried but new lever is same.i am thinking of returning it and ask for refund. Thought ask on forum if somebody might know.please help.thanks.