He spend £25,000 to animate the missing bits properly (and professionally) with most of the original cast providing the vocals. But they won't (or can't) touch it.
It's his fault if he didn't get the clearances, unless he plans to release it on his own. But I read somewhere that Sylvester McCoy was involved or something. I don't remember him playing the Doctor in 1979. And I don't think Lalla Ward was involved either and I think the actor who played Chronotis died back in 1986 so I don't know exactly how many of the "original cast" were actually involved.
That said, absolutely nothing has been announced regarding Shada other than it will be paired with More Than 30 Years in the TARDIS, so who knows what they might have planned. And the inclusion of the extant footage from the unfinished fan film Devious on the War Games set does provide some precedent.