OK so as a test I have seen on SpiceWorks that you can fudge an upgrade to 2012 by altering the registry:
Under HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\Current Version
1. Change ProductName to Windows Server 2012
2. Change EditionID to ServerStandard and then run the DVD installer.
In the example on SpiceWorks it was the R2 version but it worked for the 2012 version too.
After making these changes I was immediately able to run the 2012 set-up as stated by user BGroRud and the system upgraded to 2012 standard.
The question is - will it solve my Hyper-V issues?