Thanks Tomas,
The method choice was decided based on a few factors.
1. The environment is a Production Live environment which, through neglect, has been over utilised.
2. The stability of the cluster has been an issue which has resulted in several new clusters being built.
3. Zero or near to Zero downtime is a priority.
4. Lack of confidence in oVirt from certain quarters.
Further investigation revealed a systemd-machined.service failure on all 3 nodes in the cluster. The service will not start without a reboot, which is a non runner at this time.
A decision has been made to export and import the VMs to the new environments to avoid possibly extended outage periods.
https://lists.ovirt.org/archives/list/users@ovirt.org/message/7GGC36GIOWXL5IPR6TPWPTVW35MMYU2O/