Bathroom Mixer Tap Cartridge Replacement - Struggling Newbie!

[juniorelvis]

Hi all, newbie to this forum, and plumbing in general. I'm attempting to fix a leaky mixer tap in the bathroom (hot tap). So far I've been able to isolate the hot water supply, get the tap head off (small alan key) and am now left with the job of -I think - unscrewing the fitting behind it under the red X in the photo:

It doesn't want to budge though, I bought a strap wrench and have nearly broken the thing trying to twist the fitting (marked in red below) to get at the cartridge top (?). Do I need to try harder, which way do I turn it, or am I missing something here? Sorry for my inexperience and thanks! Additional comment: the strap wrench was slipping so I taped around the fitting, but even then the grip didn't seem great...Edit: I also sprayed copious amounts of WD40 in and on the fitting (tried to get it into the join beside the red line above). Closer look:

 

[Harvest Fields]

It turns anticlockwise and can be quite difficult if in a hard water area. I normally protect the chrome and use a good set of grips. Good luck.

 

[juniorelvis]

It turns anticlockwise and can be quite difficult if in a hard water area. I normally protect the chrome and use a good set of grips. Good luck.

Thanks! So turn away from myself. And would these be up to the job do you think? https://www.amazon.co.uk/gp/aw/d/B0...ber+wrench&dpPl=1&dpID=41FIiGj9buL&ref=plSrch

 

[king of pipes]

Always a pain bud bit if heat might help but then you need to grip it and risk damaging the chrome bit of trail and error really. Kop

 

[Harvest Fields]

Thanks! So turn away from myself. And would these be up to the job do you think? https://www.amazon.co.uk/gp/aw/d/B0...ber+wrench&dpPl=1&dpID=41FIiGj9buL&ref=plSrch

Ask around somebody local may have a set you could lend. But as I said before cover the chrome to protect it

 

[Welder]

Looking at the image you sent down the shroud, I'm of the opinion that this is unsavable. What's happened is the O-rings on the cartridge stem have been letting by and the zinc shroud has corroded to the brass of the cartridge. You will destroy it as you get it off.
Sorry, but, this time, it's a new tap. One word of advice, look for a brass tap, one that says it's made of brass. Most aren't. With brass you'll be able to keep it going for years and years with a bit of TLC.