First I ran gparted to shrink the partition and then I used the VMware converter to do the job properly. Maybe I didn't need to run gParted in the first place?
Unfortunately the process using VMware converted creates a new virtual server with the new disks and you need to then take the ONE newly sized disk and move it into the same folder as the original virtual server then you can delete the destination virtual server folder, then edit the original server's properties to include the new disk. Quite a lot to do just to shrink a volume!
I hope VMware can improve this process in the future!