Yes the house robot issue is a complex one. John can by all means licence the part of the house robots that Robot Wars LLC (not so much a brand as a limited company that owns a brand it can licence) owns, but both Mentorn and BBC Worldwide own other 'bits' of what goes into the House Robots (name rights, image rights etc).

In order to use them legally and above board, you would need rights agreements with Robot Wars LLC, Mentorn and BBC Worldwide - which is where the problem comes, once you pay your rights fees to all three, any financial benefit you might see gets eaten away. This is often an issue where you have multiple rights-holders for something, it makes them almost un-usable.

One for John to be aware of I guess, just because Robot Wars LLC has licenced John the right to use them, he still has to do his due diligence and get agreement from BBC Worldwide and Mentorn. In my view - not worth the hassle.