I did know about normalize, but it doesn't suit this particular
situation, as I want to keep all of the spaces and returns within the
text block consistent, but remove anything that the XML output format
has added.  Essentially, I want to only grab the explicit data within
the CDATA section :

                                <Calculation>
                                        <![CDATA[Table 1::Number1 & Custom 1 & External ( "Menu-
Version"; "" ) & <Function Missing>]]>
                                </Calculation>

You should really fix your XML at source - the whitespace surrounding
the CDATA section is considered significant, so really you want:

It looks as though your XML has been indented/pretty printed -
whatever did that shouldn't really have put the cdata section on a new
line.

I would say the correct solution would be to fix whatever wrote the
XML to disk, rather than patching it up at the transform stage.

cheers
andrew