This seems like quite an easy thing to do but something that had completely slipped my eyes.
I have only ever known to be able to storage vMotion all the disk in the home directory of the virtual machine I am doing. Even though eventually this is the task that I want to do, I currently am in the scenario where I have a 20GB disk, a 150GB disk and a 300GB disk, of which the task keeps timing out at 87%. Frustrating as this is, it is possible to move 1, 2 3 or however many disks you want at a time.
It is done by the following easy click…
Go through the normal steps, but once you arrive at the next screen where you choose the Datastore, click the advanced button! You will then get a drop down box of where to place the datastore. In my case I decided to move the first 3 disks and leave the 4th larger disk for a job on its own.
And there we go! Easy but also as easy to miss!