It wasn't until I was off my local network that I realised that I had been relying on my network router (to resolve the VM names) for Remote Desktop to work in this way. Double clicking on the VM in Hyper-V manager does indeed bring up the VM, but I ideally don't want to launch this first every time.
VMConnect is the tool that lets you access VMs.
At first I had a small issue when I ran VMConnect...
" You do not have the required permission to complete this task. Contact the administrator of the authorization policy for the computer ‘computername’ "
So I followed the advice on Joesph Turley's blog and added myself to the 'Hyper-V Administrators' group, restarted the machine and VMConnect could now see my VMs...
So, returning to my original problem, how do I quickly open a session to my Hyper-V VM without RDP?
The solution is to create a shortcut to VMConnect itself, passing the pc name and vm name as parameters. -
"C:\Windows\System32\vmconnect.exe" myPCname myVMname
I managed to make to launch into full screen mode, as the first time you connect you can select the resolution that it will reuse for future connections.