I have successfully replaced the filling valve to my toilet cistern and that is working fine now. But now when I turned the water supply back on at the angle stop THAT is now leaking. I double checked that it wasn't a leak coming from higher up at a bad seal at the base of the toilet and it is definitely fine and clearly coming from the little screw bit of the angle stop. I should point out that I am a complete novice. So how can I fix the angle stop? Or does it just need replacing now too?? Any advice would be much appreciated!