Ok migration of W2K8R2 with 6.2 drivers from XCP-ng 7.5 to XCP-ng 7.5 failed with msg:

Storage_Interface.Does_not_exist(_)

It also crashed the VM.

I think this could be related to https://bugs.xenserver.org/browse/XSO-785 as there is only 10GB free on the source storage repository so I don't think I can actually do the migration because of that (it's recommended to have 2x space available to migrate a VM, something that becomes increasingly harder with large VMs!).