Hi, Neil,
Usually the cause of a blank page at the end of a document is one or
more extra paragraph marks with no text. Click the ¶ button and delete
any empty paragraphs.
If that doesn't do it, check the formatting of the first paragraph of
the second page. to see whether it has "page break before" turned on
(this option is on the second page of the Format > Paragraph dialog).
If the last thing on the first page is a table, and it forces the
final paragraph mark of the document onto the second page, it may work
to format it in 1 pt font size, or slightly alter the bottom margin.
More tips are at
http://word.mvps.org/FAQs/Formatting/FitCopy.htm.