Cannot open the tap head top cap

[george987]

Hi,
I have an old tap on the bath. Please see the attached image.

Recently the water pressure is very low and flow is very slow.

I cleaned the aerator. It is clean.

The next step is to check the washer in the cartridge.

But, I cannot open the top cap of the tap.

How do I remove the tap cap. Please see the attached images.

I am not a plumber. Can anyone please help me?
Thanks

 

[just pumps]

Unscrew the dome cap above the coloured grip section.

 

[george987]

Is that golden part a screw? It is used to turn on the tap. If I turn it will just open the water.

 

[just pumps]

THE DOME CAP ABOVE THE COLOURED PART!

 

[george987]

It is not turning at all. I thought it is not removable.

 

[just pumps]

Pour boiling hot water over the dome and wearing rubber gloves gives a better grip.

 

[MickyP10]

Rubber gloves seconded! Just the dome bit unscrews.