Okay, so I managed to do this mod - but not without difficulty. I'll list my problems and how I fixed them, just incase they can help anyone else.
1.) b43-fwcutter; when installing it didn't actually prompt me to extract firmware as it apparantly should. I followed a guide on
http://linuxwireless.org/en/users/Drivers/b43 which had a link to the actual driver files, which I then extracted the firmware from using b43-fwcutter commands (I had never used linux before and I managed it following the guide on that site, so most people should be able to.)
2.) Downloading b43-tools; the link in the original post is outdated. This is the link which worked for me: git clone git://git.bu3sch.de/b43-tools.git
3.) SSB_SPROM Commands; copying and pasting the long commands from prasys blog brought up an error, as the values should be FxFFFF but when published on the web the "x" is replaced with a multiply sign. Don't let this trip you up.
Hope this helped anyone who's having trouble. My card is now reported as "Airport Extreme" and working perfectly!
Cheers