I upgraded my 7.x host to 8.3 and all VM's restored fine but one VM does not see the second HDD LVM thin pool it used to see
What should show this:

Shows this

I can see the thin pool storage exists and that it has the vm disk I was expecting to be included.

As it's not something I can select with the "Add -> Hard Disk" GUI function, I tried adding it to the vm's .conf file but that reports an error
Seems like it should have just 'restored' like everything else, and/or that there should be an 'attach' function but I'm not finding it. I can add a new disk to the pool but want to use the one that's there already.
What am I missing?
What should show this:

Shows this

I can see the thin pool storage exists and that it has the vm disk I was expecting to be included.

As it's not something I can select with the "Add -> Hard Disk" GUI function, I tried adding it to the vm's .conf file but that reports an error
Code:
vm 220 - unable to parse value of 'scsi1' - format error
size: invalid format - value does not look like a valid disk size: 1TB
Seems like it should have just 'restored' like everything else, and/or that there should be an 'attach' function but I'm not finding it. I can add a new disk to the pool but want to use the one that's there already.
What am I missing?