Just a quick update, I will post a more complete one once I have properly documented my progress.
Since it seems too painful to work out how to get it working in windows server SBE 2011 domain controller (which I THINK seems to be similar to server 2008?) I have managed to convince the IT guy to use one of our other 3 running server 2012 instances to run the DHCP server.
I have created a windows 2012 server VMWare VM and set the DHCP server up as per @Wayne-Workman’s excellent article https://wiki.fogproject.org/wiki/index.php/BIOS_and_UEFI_Co-Existence
I added a Vendor class for the IP phones and the PC types listed here https://wiki.fogproject.org/wiki/index.php/BIOS_and_UEFI_Co-Existence#Example_1
I then added the scope polices as described in the example. It is this ability to add scope policies that Windows Server 2008 is lacking.
I find it incredible that the DHCP service cannot just be upgraded/replaced to have this functionality.
FOG is installed on a CentOS VMWare VM that @Wayne-Workman generously helped my set up. I had installed it all but for some reason the installer did not complete (probably my fault) as /opt/fog/.fogsettings did not exist.
I have since captured and redeployed and XP and a Win7 image for testing purposes. The next step I assume is to try and build a universal HAL image.