Hi there, 

I cannot locate the adjuster nut in cabin for Fabia mark II. 
Tried removing plastic around arm rest and can’t see where it terminates.

 

The adjuster nut is hidden by the weird shaped casting that supports the arm rest.

This is the way I did it, but there may be easier ways:

Prise away the trim panel on the passenger side of the arm rest support.

Then undo the arm rest pivot screw and remove the arm rest. Undo the screws holding the centre consul. They are under the rubber mats in the front and rear cup holders. This will give the consul enough freedom of movement to access the 4 screws holding down the previously mentioned casting. You'll need a long extension to your wrench, with a universal joint on the end to reach the screws. They are Torx but sorry,  I can't remember the size. Then wriggle out the weird casting to reveal the handbrake adjuster nut.

I hope this helps.