double bar number

[bb]

I want bar numbers for every bar and a low bar number position to avoid
interference with the chord names. My first attempt shows two bar
numbers one over the other. I do not want the second, the upper bar
number. I cannot find a solution. Thanks for help.

\version "2.19.80"
chordsone = \chordmode { c1:7  f1:7 c1:7 }
one = {
\relative c {
\override Score.BarNumber.break-visibility = #all-visible
\clef "bass_8"
  c,4 g' c, ges' | f c' f, des |c g' c, as' |
}}
\score  {
  <<
        \new ChordNames { \chordsone }   
        \new Staff
        \one
 >>
}
      \layout {\context {
    \Staff
    \consists "Bar_number_engraver"
  }}