I think I need to change the diaphragm washer on my toilet cistern. Water keeps pouring into the toilet even after flushing has stopped. It's an Ideal standard, about 6 years old. Someone did show me the last time I needed to do this, but I've forgotten. Then the old washer had developed a hole, so I'm imagining it's the same problem. I'm struggling to access inside the ballcock, as everything seems firmly fixed in place. I've taken photos. Does anyone know how I can upload them here. Or does someone know how I can access the old diaphragm washer, which is Armitage shanks no. SV90167. Thanks.