Dripping tap - washer change Drainage and wastage systems and plumbing help, advice and answers

[cotswoldmark]

Hi All - I thought this was going to be an easy, quick job. We've a dripping tap in our WC. I'm therefore looking to change the washer.
I've been able to disassemble most of the tap, but cannot get to the valve that houses the washer (I assume).
I'm trying an anti-clockwise unscrew, but it's not budging, even with some force.
Can you advise if I am actually doing this right?

[Mr White]

Try a "box spanner" as it grips all sides at the same time, also try going the other way just a tiny bit.