Extra white space for Chordnames

[Basso Ridiculoso]

I would like to increase the amount of whitespace between the chordnames and the staff below them, but am having no success. I have tried some variation of all of the following with no results.
 
\override Staff.VerticalAxisGroup #'minimum-Y-extent = #'( 4 . 4) (with negative and positive values)
\override Staff.VerticalAxisGroup #'Y-extent = #'( 10 . -10)
\override VerticalAxisGroup #'staff-affinity = #DOWN (also tried up)
\override VerticalAxisGroup #'nonstaff-relatedstaff-spacing #'padding = #20
 \override VerticalAxisGroup #'nonstaff-relatedstaff-spacing = #'((basic-distance . 10))

\score{
<<
 \new ChordNames  {
        % \override VerticalAxisGroup #'nonstaff-relatedstaff-spacing = #'((basic-distance . 10))
 \chordmode {  c2 f c f }
 }
 
 \new Staff {
%%\override Staff.VerticalAxisGroup #'minimum-Y-extent = #'( 4 . 4)
 %%\override Staff.VerticalAxisGroup #'Y-extent = #'( 10 . -10)
%  \override VerticalAxisGroup #'staff-affinity = #DOWN
 %  \override VerticalAxisGroup #'nonstaff-relatedstaff-spacing #'padding = #20
       
 \override VerticalAxisGroup #'nonstaff-relatedstaff-spacing = #'((basic-distance . 10))
         
                    \relative c'{ c4 d f a c4 d f a}
 }
>>
}


What the heck is the magic command to add some space? Am I putting in the wrong place?

Daniel