Thanks, Thomas that worked well. Unfortunatley my include for the XML file is in the middle of a php document. I have lots of code outputted before I actually output the XML so if I use the header function I generate an error. Can you think of any other methods?
Heres the error although I'm sure you are familiar with it.
Warning: Cannot modify header information - headers already sent by (output started at /path/filename.ext :1) in /path/filename.php on line 9