Mono mixer tap cartridge removal recessed nut

[whhaatt]

I am trying to replace the cartridge for a waterfall tap (mixer mono) for the bathroom sink, I have run into a problem whereby I cannot remove the cartridge as the usual 32mm nut is recessed and I cannot get to it. The tap is from screwfix (

NIAGARA WATERFALL BASIN MONO MIXER TAP)​

I have attached a photo, I must be doing something wrong as I cannot find a tool for this too, or is their some sort of O ring that I need to remove?

 

[snowhead]

The tool will most likely be manufacturer and possibly even tap specific.
There may have been one included in the original box the tap came in.

I can't see too clearly into the recess but usually there is a lock ring that holds the cartidge in place.
The ring will either have flats on the outer of inner edge for a box spanner type tool to grip or slots.

Failing that there may be pin holes facing up in the lock ring for a tool to fit in.

Is there any makers name or a photo showing the complete tap with handle and a clearer picture looking down into where the cartridge is?

 

[whhaatt]

The tool will most likely be manufacturer and possibly even tap specific.
There may have been one included in the original box the tap came in.

I can't see too clearly into the recess but usually there is a lock ring that holds the cartidge in place.
The ring will either have flats on the outer of inner edge for a box spanner type tool to grip or slots.

Failing that there may be pin holes facing up in the lock ring for a tool to fit in.

Is there any makers name or a photo showing the complete tap with handle and a clearer picture looking down into where the cartridge is?

The tap in question is
screwfix url ending in /p/niagara-waterfall-basin-mono-mixer-tap-with-clicker-waste-chrome/2054p

It looks like other people are having the same issue on the Q&A section for the tap on the website.

I will try again to see if I can locate lock ring.

 

[ShaunCorbs]

For £60 ish quid might be best just to replace the tap