I've created my storage pool incorrectly. I'm using LVM and I have a volume group called vms-lvm. 
When I look at it in virt-manager I see that the volumes it contains are home, root and swap, so when I created the storage group in virt-manager I must have specified something incorrectly.

Unfortunately I can't find a way to correct this. If I try to destroy (stop) the storage group I get an error:

# virsh pool-destroy vms-lvm
error: Failed to destroy pool vms-lvm
error: internal error: Child process (/usr/sbin/vgchange -aln centos_hyv2) unexpected exit status 5:   Logical volume centos_hyv2/swap in use.
  Can't deactivate volume group "centos_hyv2" with 3 open logical volume(s)

Same if I try to undefine it:
# virsh pool-undefine vms-lvm
error: Failed to undefine pool vms-lvm
error: Requested operation is not valid: storage pool 'vms-lvm' is still active

Can anyone please advise how I get out of this mess? There must surely be a way of undefining this?