>  held in the <ext-link> elements are 
> stripped out. This means that semi-colons, commas and other punctuation is 
> then left behind and this looks especially bad 

If you only want to lose punctuation that was by one of those elements,
just do so.

<xsl:template match="text()[preceding-sibling::*[1][self::ext-link]]">
  <xsl:value-of select="replace(.,'[,;]\s*$','')"/>
</xsl:template>

<xsl:template match="text()[preceding-sibling::*[1][self::ext-link]]">
  <xsl:value-of select="replace(.,'^\s*[,;]','')"/>
</xsl:template>

which, If I got that right, just removes ' and ; (and following white
space) from the end of a text node that's followed by ext-link
and similarly zaps punctuation from the start of text nodes that folloe
ext-link.

David

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