^ Interesting. So, if my theory holds, no multi-Doctor special. Although, I suppose they could still air The Five Doctors or The Two Doctors. But, could this be a step to not fan the fires for a multi-Doctor special?
I'm surprised they picked Spearhead. It's a bit slow in my opinion and there are better 4 part options available, including Terror of the Autons if they wanted the Autons. I think Terror does a better job with the Autons too and intros the Master. YMMV.