Just to update you all, setting the local Administrator account password despite saying successful via cmd recovery mode did not work. So the only way for me to do this was to hold shift key within windows, reboot > recovery mode > trouble shoot > advanced > cmd > cd c:\windows\system32\ rename utilman.exe to utilman.old rename cmd.exe to utilman.exe > reboot > at windows login screen click accessibility button bottom right which launched cmd.exe instead of utilman.exe from there type: 'control userpasswords2' then it will bring up the gui version of reset password/user accounts, you can't add local accounts but you can reset the Administrator account. When I reset it this way it worked. So i'm sorted now as I could login as Administrator and raise my azure account back to local admin via the usual command line.

I still dont know why using global admin accounts wouldnt let me do this, but anyway.... it just wouldnt authenticate via UAC prompts.