I am a freelance writer based in Australia. I often sell my features
overseas, especially to the UK and the US. I have used Microsoft's
grammar and spell check but have found it useless. I am looking for
advanced spelling and grammar software that will allow me to:
*Change documents between US, Australian, UK and other English.
*Double space documents.
*Correct only spelling and grammar, not my writing style.
I am after a short list (2 or 3 products) of premium products. Thanks in advance.

Hi! You CAN do most of this right in Microsoft Word:

>>>*Change documents between US, Australian, UK and other English.
The common mistake? You must FIRST select all! Then change the
language. So, Ctrl+A, Tools-->Language, choose it.
>>>*Double space documents.
Probably again: You must Ctrl+A, then Format-->Paragraph, and change
line spacing to double. We can even make it the default if you like.
>>>*Correct only spelling and grammar, not my writing style.
I'm not positive about this one, but there are many settings under
Tools-->Options-->Spelling and Grammar. You can change the writing
style.

Another thing you should know about S & G...
Many people aren't aware that once you spell-check a document and
accept/ignore things, those accepts/ignores are stored in the
document. If you were to, for instance, Ctrl+A and change the language
from US to UK, you'd then want to spell-check again, yes? In order to
"dump" those saved items, you need to go to Tools-->Options, S & G,
and hit Recheck document. That could be automated to a toolbar button
for you, if you wanted.