Rich,
I believe you could try something like
<xsl:text
disable-output-escaping="yes"><![CDATA[ ]]></xsl:text>
So in your case, you could do:
<xsl:template match="/">
<html>
<body>
<xsl:text
disable-output-escaping="yes"><![CDATA[£]]></xsl:text>
<xsl:value-of select="data/premiumAmount" />
</body>
</html>
</xsl:template>
You can think of it as outputting the entity to your result, which would
be your HTML document, but disabling it at the time of the XSLT
processing.
Regards,
Chris
XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list