Add xml element immediately after another element

I have this xml

  <request_scope>
     <valuation_currency>GBP</valuation_currency>
     <fund_code_type_required>FUND1</fund_code_type_required>
     <valuation_request type="Current"/>
     <valuation_request type="Surrender"/>
     <fund_breakdown_request>yes</fund_breakdown_request>
  </request_scope>

and I want an xslt that adds element intermediary immediately after fund_code_type_required
only if intermediary does not exist. So to be

   <request_scope>
      <valuation_currency>GBP</valuation_currency>
      <fund_code_type_required>FUND1</fund_code_type_required>
      <intermediary></intermediary>
      <valuation_request type="Current"/>
      <valuation_request type="Surrender"/>
      <fund_breakdown_request>yes</fund_breakdown_request>
   </request_scope>

Just match fund_code_type_required when it's a child of request_scope and doesn't have a sibling intermediary. Output a copy of fund_code_type_required and add the new element after...

<xsl:stylesheet version="3.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" expand-text="yes">
    <xsl:output indent="yes"/>
    <xsl:strip-space elements="*"/>
    
    <xsl:mode on-no-match="shallow-copy"/>
    
    <xsl:template match="request_scope[not(intermediary)]/fund_code_type_required">
        <xsl:copy-of select="."/>
        <intermediary/>
    </xsl:template>
    
</xsl:stylesheet>

Fiddle: http://xsltfiddle.liberty-development.net/94humqD