Device won't add and now can't remove - solved

Well here we go again with another two minute job that's taken hours so far.

1 - Tried to add new device Aeotec Nano Switch and it wouldn't include. Was showing in Z wave details page.
2 - Tried "Discover" - nothing.
3 - Tried to exclude - nothing
4 - Switched off power, tried to "remove" - nothing
5 - Added Z Stick as secondary controller and fired up PC controller, selected node, clicked "is failed" - failed to mark the device in red and brought up a failed message
6 - Clicked "NOP" - the PC controller software shows "send NOP started" but just goes forever.

Have already rebooted, powered down HE etc. Where on earth do I go from here. I'm at the point where every time I want to add a device to my setup - excitement turns to anxiety and complete panic of what's to come.

Edit: After several hours with PC controller hanging for 10 minutes plus on "send NOP started", before attempting to remove the failed node nd failing in 4 seconds it's finally cleared.