Remove a Circle from Plugwise network

[Cariba]

I've got a replacement for my plugwise circle from the helpdesk.
The circle I had had an un-updatable firmware version.

Now that I've got my new circle (with another MAC address), I can't remove the old circle from my network. Any suggestions?

I even tried to remove it from the database, and that worked, but when I search for new modules it still finds the old circle.