Lalla's in it. All of the living cast except Tom. As you Denis Carey died in the 80s, David Brierley is no longer with us, so he got John Leeson to voice K9. The gent playing the porter also died, but his scenes were all completed.
Sylvester isn't in his Shada, he got him to film visual footage for his Downtime, Search Out Science and Destiny Of The Doctors Special editions.
He can't release them on his own, he did them on the hope the BBC would pick them (or at least Shada) up. He was behind getting the lost sequences of Planet Of Giants redone, and they will be an optional extra on the DVD later this year.