So I read this today. I'm not an expert on British copyright law but I can't imagine for a minute that this has any legs. The concept of a time/space craft with variable outter dimensions but larger inner dimensions was created before Coburn even was assigned to right the first story. Once the budget ensured that the ship would need to get stuck in a certain appearance he was the one who decided on a police box and I believe he came up with the acronym "TARDIS". I can't imagine that's enough to give him ownership of the rights to the TARDIS. This is so absurd that I wonder what his son hopes to gain? Does he think that the BBC will just settle with him to make it go away during the anniversary? That's the only thing that I can figure.