Bibliography, v5, titlepage template

My template is
<t:titlepage t:element="bibliography" t:wrapper="fo:block">
<t:titlepage-content t:side="recto">
<title
          t:force="1"
          t:named-template="component.title"
          param:node="ancestor-or-self::bibliography[1]"
          margin-left="{$title.margin.left}"
          font-size="12pt"
          font-family="futura"
          font-weight="bold"
          text-align="center"
          space-after="33.161mm"
          color="rgb(40%,40%,40%)"/>
<subtitle
         font-family="{$title.fontset}"/>
<author
        font-size="13pt"
           space-before="12pt"
           text-align="center" />
</t:titlepage-content>



and I'm seeing

<fo:flow flow-name="xsl-region-body">
<fo:block id="the0001789">
<fo:block>
<fo:block>
<fo:block margin-left="0pt" font-size="12pt" font-family="futura" 
font-weight="bold" text-align="center" space-after="33.161mm" 
color="rgb(40%,40%,40%)">
<fo:block xmlns:axf="http://www.antennahouse.com/names/XSL/Extensions" 
keep-with-next.within-column="always" space-before.optimum="10pt" 
space-before.minimum="10pt * 0.8" space-before.maximum="10pt * 1.2" 
hyphenate="false" text-align="start" start-indent="0pt" 
line-height="1.3" hyphenation-character="-" 
hyphenation-push-character-count="2" 
hyphenation-remain-character-count="2">Further Reading</fo:block>
</fo:block>
</fo:block>
</fo:block>
</fo:block>

Of note:
I specify text-align='center'
the inside block overrides this, with text-align='start'

What am I missing please?

TIA

regards

-- 
Dave Pawson
XSLT XSL-FO FAQ.
http://www.dpawson.co.uk