The Starwind converter I tried is great! I used it to convert my Ubuntu instance and it worked first time without any error or fuss. Didn’t even need to read the instructions. That’s the kind of tool we all like.
Of course, every silver lining has a cloud and in this case after I was happily using my new VM on Hyper-V my entire Windows 8 second boot disk died a death. A calculated risk as the disks were old, re-cycled SSDs.