GST returns.  If she is one of these people then she would be better
served financially by learning these skills via some course because if
she doesn't she will be paying through the nose in Accountancy costs.
    

Hence the "I don't know".

There is a tendency among geeks to take everything at face value.  Her 
request was vague, and my knowledge of this area is extremely limited. 
I assumed people here will know more, so I asked! :)

I agree with your suggestion though, and will suggest this to her.
  

Because she, like many of those adopting F/OSS software for the first 
time, admires the ideology, but is not quite ready to leap in and run 
!Windows just yet.  She will cope with Linux if it's single use, but her 
family are dependant on the windows box, and so she thought it would be 
nice if it also ran on Windows.  I'm not sure what you mean by "undeserved"?
  

If that is the best answer, she'll probably just buy the non-free stuff 
and run it on Windows, as $DEITY intended! ;)  She's not a F/OSS Zealot, 
merely enquiring about alternatives, and would like to do the F/OSS 
thing if possible.

  

In my experience (supporting lots of accountants) they LOVE to run the 
same software that their clients do, so they can just grab the data and 
work directly on it.  Some of them value this ability so much that they 
will have a dedicated machine running heaps of different accounting 
packages just so they can do this.  So there's a different view for you. :)