AFAIK, it's not possible to remove the US dictionary; all you can do is try to suppress it.
You need to make sure your system locale is set to UK and set the Office Language to UK via Office Tools (I think that's in OfficeXP as well as Office2003)
The big problem occurs when you open a DOC file which is uses the US dictionary; Word does not seem to indicate a change of language and does not revert back UK automatically, even if detect language automatically is disabled.
It is compounded further because Document Scanning and Imaging is only US, and any scanned file defaults to US irrespective of Word existing defaults.
LIVERPOOL FC - FA Cup Winners 2006.
Iechyd da! John
Glannau Mersi, Lloegr.