I've managed to delete the domain through HSphere control panel. I selected the checkbox of the domain I wanted to delete, pressed submit, and was then taken back to the same page. I then DESELECTED the checkbox and pressed submit again. For some reason it deleted the domain when the checkbox was deselected.?(
I've noticed a few times on this forum when I've pressed a button(e.g. post reply) I've received a blank page and I've had to refresh my browser. Maybe this is an unrelated issue.