Centring a heading, including the numbering

Question

I've got a problem that should be simple to fix. I'm using the fontspec to layout my chapter headings like so

%!TEX TS-program = xelatex
%!TEX encoding = UTF-8 Unicode
\documentclass[oneside,a4paper,10pt]{book}
\usepackage{titlesec}
\usepackage[utf8x]{inputenc}
\usepackage{fontspec}
\titleformat{\chapter}[hang]
  {\normalfont\fontsize{25}{30}\bfseries\centering \fontspec{Times New Roman}}}
  {\chaptertitlename\ \thechapter:\space }{0pt}
  {}[]
   \begin{document}
   \chapter{The Road In The Wood}

   \end{document}

and for the most part it works just as I want. There is however one slight issue, some of my chapter headings run onto two lines - that's fine. However instead of centring the the second line properly it's placed towards the right of the page.

I believe what it's doing is centring as though the page begins just after the "Chapter 1" part of the heading. Is there a way to tell it to center based on the whole page?

Answer 1

I've succeeded with

\titleformat{\chapter}[hang]
  {\normalfont\fontsize{25}{30}\bfseries\fontspec{Times New Roman}}
  {}
  {0pt}
  {\centering\chaptertitlename\ \thechapter:\space}

However I wouldn't use \fontspec, but rather

\newfontfamily{\timesnr}[Ligatures=TeX]{Times New Roman}

and \timesnr instead of \fontspec{Times New Roman}

Never use the inputenc package with XeLaTeX.