Hi Yes, this is my situation
And could I confirm these things?
1. Is the vMotion for single or dual VMs between DCs working correctly?
Single and dual vm vMotion is working correctly - any more than this and it sticks on "validating"
2. Did you reboot your vCenter Server?
vCenter has been updated and performed reboot as part of this process previously and still not working
3. Did you restart hostd/vpxa in each ESXi hosts?
Hosts have been rebooted, services restarted
4. Did you reboot your ESXi hosts?
Yes hosts have been rebooted (cold reboot)
Very Strange indeed.