Looking for advice - loose mixer tap unusual fitting

[Kathryn McDermott]

Can anyone help me, I need to tighten this tap but it has an unusual fitting and I can't fathom out how to fix it. I'm not even sure what's it's called to search for it. Thanks in advance!

 

[Chalked]

Hi
Pull out the pop up lever stem. Once you have done this you will see that there is an Allen key location inside the threaded bar. You tighten it from there

 

[Kathryn McDermott]

Hi
Pull out the pop up lever stem. Once you have done this you will see that there is an Allen key location inside the threaded bar. You tighten it from there

Thank you so much, will give it a try.

Sorted, complete success thanks again!