DOCBOOK-APPS: xref problems

I have

<appendix id="ch12Ex1">
   <title>Examples for <xref linkend="ch12"/></title>
   <example id ="ch12ex1">

I.e. this is a chapter which contains examples for another one.
XSL 1.44 for html doesn't show the link up,

http://www.dpawson.co.uk/xsl/sect3/bk/ch12Ex1.html

Is it something that was recently cleared please?

Regards DaveP