header not showing bookpart-score header info

[Kieren MacMillan]

Hello all,

Why is the header not showing up here?

\version "2.19"

\paper {
  print-all-headers = ##t
  bookTitleMarkup = \markup \abs-fontsize #72 \fill-line { \center-column { 
\fromproperty #'header:title \vspace #4 } }
  scoreTitleMarkup = \markup \abs-fontsize #48 \fill-line { \fromproperty 
#'header:piece }
  oddHeaderMarkup = \markup \abs-fontsize #12 \fromproperty #'header:piece
  evenHeaderMarkup = \markup \abs-fontsize #12 \fromproperty #'header:piece
}

\header {
  title = "Book Title"
}

\bookpart {

  \score {
    c''
    \header { piece = "In C" }
  }

\pageBreak

  \score {
    d''
    \header { piece = "In D" }
  }
}

Thanks,
Kieren.