Replacing a washer on a tap

[PierremontQuaker]

Hi, I have a seriously annoying dripping tap which is getting worse. I have included some pictures.
I need to replace the washer. Has anyone came across these sorts of taps. as you can see from the picture the bath has been tiled in so I cannot get access to underneath without taking the tiles off - which would be a complete pain. Do you think the silver full unit will pull off if I use some brute force or do you think it will be screwed in fro underneath? Any advice would be much appreciated!

 

[SimonG]

It's not a washer, probably a cartridge.

I would say you are going to need access to the underneath.

Personally I would be giving whoever installed that, a really good slap.