Can't Live Migrate or move Hyper-V VM

we have a two-node Server 2019 Hyper-V cluster with an SSD SAN providing the shared storage. I'm in the process of trying to update the host servers with their windows updates.

I planned to move all the VM's from Host-01 to Host-02 install the windows updates on Host-01, then move all the VM's to Host-01 and repeat the process on Host-02.

I managed to move all the VM's to Host-02 except 1 Server 2012 VM which when I try to do a live migrate gets to about 62% then simply stops migrating and remains on Host-01.

If I try to Move the VM instead of live migrating, it appears on Host-02 but with a big red X on it and it then refuses to start.

The event logs show the following errors:

Event ID: 1205 - The Cluster service failed to bring clustered role <<'MY Server'>> completely online or offline. One or more resources may be in a failed state. This may impact the availability of the clustered role.

Event ID: 1069 - Cluster resource 'Virtual Machine Configuration <>' of type 'Virtual Machine Configuration' in clustered role 'SVR-IIS-INTRA' failed.

Event ID: 1254 - Clustered role '<>' has exceeded its failover threshold.....

Event ID: 1205 - As above

Event ID: 1069 - Cluster resource 'Virtual Machine Configuration <>' of type 'Virtual Machine Configuration' in clustered role '<>' failed. The error code was '0x5' ('Access is denied.').

Event ID: 21502 - 'Virtual Machine Configuration <>' failed to register the virtual machine with the virtual machine management service.

The Virtual Machine Management Service failed to register the configuration for the virtual machine '03059663-1988-4147-929F-4D543925C4EA' at '\\host-01\c$\ClusterStorage\Volume1\<<My Server>>': General access denied error (0x80070005). If the virtual machine is managed by a failover cluster, ensure that the file is located at a path that is accessible to other nodes of the cluster.

The last 2 / 3 error events were generated when attempting a standard move rather than a live migrate. I've checked that both hosts can access the above folder location so I'm at a bit of a loss.

If push comes to shove I will have to create a new VM and move the disk but if anyone knows how to fix this I'd be grateful.

To be clear I have over 40 VM's (20 per host) and this is the only one that is refusing to move. All VM's use the same CSV (1).

Thanks for any thoughts.

Paul.