How Can I Remove This Mixer Tap?

[pauls68uk]

Hi,

I have a leak at the base of the kitchen mixer tap where it goes into the sink. I can remove the spout easily but I can't get the base bit off.
Under the sink next to the hot & cold pipes going up through the sink to the tap is a black rod type thing. It seems to be made of hard plastic and it has a hexagonal end with a slot in. Does this unscrew to enable the base of the tap to come off. I have tried to unscrew it but it seems stuck and I don't want to force it. I have attached a couple of pics to show the black 'rod'.
Any help would be gratefully received.
Thanks,
Paul.

 

[ChrisR]

yes it undoes.
Socket set does it, see post currently one above.

 

[pauls68uk]

Thanks for that Chris. I'll give it a go.

 

[bster]

If you havent got a socket set 'MONUMENT TOOLS' do a monotap back nut set for £3 odd. available at most plumbing merchants.