Help removing rusty kitchen tap fixing

[aveatry]

First off what am I looking at here. Do I see some sort of back nut amongst all that rust. And if that is how the tap is fixed to the sink then what is the purpose of the plastic part with the slotted end.
I am trying to find a photo example that is not rusted so I can see what I am up against, I do not have direct access to it at the moment, its for a long distance friend. I will be swapping the tap.
Thanks

 

[HERTS P&D]

Undo the plastic fixing, large screwdriver might work or box/tap spanner set.

https://www.amazon.co.uk/NeishTools-Monobloc-Spanner-10-11-12-13mm/dp/B0757W3BZH/ref=sr_1_2_sspa?dib=eyJ2IjoiMSJ9.LPFW-JfUQdJ8J2Vwwg6NddKR7hRHR-cOET5F_mjeMd40V9vIh-YZfRejgjlUNxCnexI_Wl72Mx_qEgnLU5lpDk1R9BqacFLnJEqeQo_0jAsndKmfM0WTH77L5k9DIl_qWzot7U-ZvRr3qklNQ15oZA5SORmsnY5Dh3A35gjL97fwN4T39_HA3_qqyQDan_FurvYncmQVoFJKhMVqWa8Te1xNlc-huLgU5vz0Ikk8QXgVGTPkS78Cx68RPp5rtCHxiDWz5BWim1rvaNj6sMv73d2kZavlC1WEelYHcwlrDpo.1NX9O6IC-Sk9ZG8QV49qByKrKa94c5nkRlk3RqdiAsE&dib_tag=se&keywords=tap+spanner&qid=1713426468&sr=8-2-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

Andy

 

[aveatry]

Thanks I have the box set after replacing my own kitchen sink but that plastic bit on my tap was brass with the separate long nut that gos on to clamp a horseshoe under.
This one looks to be just a plastic shaft but I can not see what it is doing.

 

[aveatry]

Here is the tap. It is leaking from the spout to body - as you can see. I may just try replacing the o rings in there. The spout is also wobbly.

 

[gas112]

Flat blade screwdriver into that plastic shaft . New tap will come with new tails or flexis so just snap existing ones out the way

 

[aveatry]

Flat blade screwdriver into that plastic shaft . New tap will come with new tails or flexis so just snap existing ones out the way

Thanks.
So is it my imagination that I am seeing amongst the rust and scale flat sides on that ring under the sink or is that just a normal horse shoe affair.
A plastic screw in shaft seems really rubbish for holding a tap. I know the metal ones are similar but they have a wider nut that goes on - this seems to be relying on a smaller thread on top of the wider shaft body perhaps.
I don't have much confidence in it unscrewing.

 

[aveatry]

OK An Update.
I have cleaned the area and I can now see what is going on. it is indeed a normal horseshoe some of it completely rusted away held inplace with a plastic screw in shaft. there is a rubber seal then a stainless metal ring/ washer and then the horseshoe.
It doesn't look like it will hold up much of a fight when I want to remove it.

 

[aveatry]

Another update .
I removed the spout and the two o rings were completely knackered. I managed to find an O ring from my big box of o rings that fit gave it a smear of the proper silicone grease and when I left the leak was fixed.
1 point with my O ring set is that out of the 32 different sizes I never seem to be able to have the exact right size - so frustrating its a kit just like this one https://www.amazon.co.uk/HFS-Universal-Assortment-Metric-A
It was an R12 but the fatter version was too fat and the thinner one that I used seemed a little too thin - I needed something in between -- ahhhh