OK, 1 day later and succeeded in getting VGA Passthrough working, I kept getting the agp BSOD, so decided some of the other suggestions to downgrade to V5.0, but of course my Network Adapter was not recognised, so tried patching with same package as with 5.1, but after trying the custom 5.0 iso and burning 5 DVDs, all failed, unlike 5.1 patched iso which worked first time, time spent on that probably 4 hours !
So I decided to revert back to 5.1 and started to make mods to the BIOS, after several individual changes and reboots, finally discovered that the onboard GPU needs to be disabled as well as multi GPU support and IGPU memory allocation must be set to auto EVEN IF IT IS DISABLED !!
Now have VGA Passthrough working on windows 7, but that it not my goal, I am aiming for XBMCbuntu - has anyone succeeded with this ??
I have tried passthrough both onboard and off=board USB controllers, it allows me to add them but after a reboot the PCI USB controllers are not available for passthrough, even after adding them priior to the reboot.
Also, NONE of the connected USB devices can be added to the VM, I have a feeling this project is only at it's very early stages !!