I recently moved into a new apartment and have a slow leak from the left faucet handle in the bathroom (given the build up you can see in the photo, it’s probably been leaking for a while). I assume I just need to change the cartridge but I can’t find the screw to release the handle so I can get access. I’ve unscrewed the hexagonal cover and pulled it up but there’s nothing there. I’ve also tried prying off the top cap (the ‘H’ in the photo) in case it’s under there but it sits absolutely flush so I can’t get any leverage to get it off. What am I missing?