Cannot delete snapshots on VNX5300

I have a VNX5300 SAN which has LUNs which were migrated from a temp SAN and now I have snapshots on the VNX which I cannot delete.

Here's what I can see:

Data Protection\Source LUNs:

LUN1, Type=Source LUN

+-- SANCopy_FAR_LUN1_WWN_Destination, Type=Session

LUN2, Type=Source LUN

+-- SANCopy_FAR_LUN2_WWN_Destination, Type=Session

LUN3, Type=Source LUN

+-- SANCopy_FAR_LUN3_WWN_Destination, Type=Session

When I click on the Source LUN, the buttons available are "Properties". If I click on the Source LUN, I can see the snapshot in the Snapshot Details pane, but the only button available to me is the Properties button.

Sessions & SnapShot LUNs tabs are blank.

My question is, how can I delete the snapshots using the GUI?