Success!
I have a triple boot HP 4540s running Mac OS 10.8.2 Mountain Lion/Windows 7, 64bit/Linux Mint 14, and I'm a very happy camper!
Thanks go to all the many folks on Tonymacx86 who have not only used their knowledge and skill to make this possible, but too also share their hard earned techniques with the rest of us, thank you all.
I just need to tidy up the install, but all basic functions seem to be working OK at the moment (sound/video/wifi etc.) but I still need to sort a UK keyboard layout and test stuff like HDMI.
I will attempt to post a how to (if I can remember what I did
) if no-one else (better qualified) wants to do it?
Pete