As i was installing a flex cable with valve moments ago i fitted it and decided to flush the toilet. To my disbelif i noticed that the nut under the toilet tank was dripping. It must have been doing it for months without me ever noticing but i am 100% sure when i replaced everything in the bowl this was not dripping then. Anyway i suspect it to be the rubber washer or the metal plate, there must be a hairline crack somewhere which is causing it to drip. I have found the coupling kit on screw fix but all i really need is the plate and the rubber washer. I cannot for the life of me find these as seperate items on screw fix. The reviews for the kit are also mixed, mainly due to the metal plate being extremely thin, I was thinking as a quick fix to use sealant with the rubber washer to give it more volume? Would this work?