@Don-Gould-NZ I wonder if this system got cloned as intended. I see 2 devices in XO, that will be xvda and xvdb. Yet earlier you listed it was one device with two partitions. The 512M size of the 2nd device makes me wonder if the migration turned the disk partitions into devices with partition/swap signature and nothing else.

As such since the system looks for xvda's 2nd partition for root, there's no partitions so naturally it fails.

You could get SystemRescueCD, boot off that and investigate the devices.