Problem removing tap unit to change washer

[EchoBeach]

Hi
Our house is 11 years old.
There are a couple of (basin) hot taps that will drip if not tightly turned off.
Recently I attempted to change the washers therein.
I get as far as trying to remove the main central unit that should have the washer on the bottom.
However, try as I might, I am unable to release this part of the tap.
I've tried bracing the tap itself, but the tap and its local piping through the sink is 'weaker' than the jammed central unit.
To avoid critical damage, I have stopped.
Please can anyone suggest techniques for loosening the central unit.
Echo

 

[Charnwood]

To avoid potential damage to the sink, have you thought about removing the tap completely, then brute force could be exerted.

 

[Terry7556]

100% agree, remove tap, transport to nearest vice and give it some