So, downed the VM's.
Put the host in maintenance mode.
Upgraded to v5.1
Then had issues with DNS on vsphere client as VM's virtual
Managed to log into the host (local storage) with onboard SD card with install
powered up VMs and had message;
This VM might have been moved or copied blah blah blah...
I answered copied (as it reccomened that)
Powered up VM;s
Now some of them have lost static ips and picking up DHCP ones.