I managed to manually transfer a VMDK and Vmx file across from one datastore and now have copied it to another. So both .vmx and .vmdk files are sitting in the same location.
However, I don't know how to fire it up. I went to the datastore location and right clicked on the .vmx file and did 'add to inventory'.
But I'm sure there's something I'm not doing right here as I've attached the picture error.