Hey Raetke,
Thanks for your advice, it sounds hopeful that this may be where I am going wrong as I did not run Win10 1909 prior to re-building my 7.11 Horizon View system.
I did try running a Sysprep / generalize before capturing the master VM image in a snapshot previously, but when the VDI clones boot, they boot into OOBE experience and don't get domain joined etc.
Am I going wrong here somewhere with the Sysprep / customisation process before capturing the master VM snapshot, perhaps?
Rgds
Gary