I’m feeling pretty proud of myself, having fixed our powder room toilet, which over the past few months haw gradually suffered a decline in its ability to refill after flushing. I had previously replaced the stopcock assembly and checked the whole thing for leaks, but with no effect. Turns out the cheap rubber washer in the inflow valve had come loose and blocked the pipe, growing steadily worse as deposits built up. One hard plastic washer of identical size later, the toilet works like it did when it was new. Bow before my mad plumbing skillz, minions!