If you created the duplicate header by copying and pasting, you will have
added an extra empty paragraph (no matter how carefully you select the text
you copy and paste, this still happens). This is causing one header to be
higher than the other. Display nonprinting characters (Ctrl+*) so you can
see the paragraph mark and delete it.

--
Suzanne S. Barnhill
Microsoft MVP (Word)
Words into Type
Fairhope, Alabama USA
Word MVP FAQ site: http://word.mvps.org
Email cannot be acknowledged; please post all follow-ups to the newsgroup so
all may benefit.

"Colinhp" wrote in message
...
I have a double sided word document with headers and footers set up as the
same measurement. The footer style is all the same and and header style
is
all the same. The page margins are set up the same for the whole
document.
The document is also set up as mirrored margin.
When printing the document on one side of paper all the footers and
headers
are exactly as expected. The print preview matches what I get.
When I print the document double sided the odd page headers and footers
are
approx. 2mm higher than the even page header and footers. I have recently
updated the print driver which is working fine.
On other documents not set up for double sided printing in the template
they
all print fine but this document has been specifically been set up for
double
sided printing and the headers and footers have this 'glitch'.
The print preview through both Word and the printer shows that the headers
and footers are fine.
Please can you help. I have searched many sites and have found nothing
about this problem anywhere.