I watched the re-edited 66 min long version of this. This was enjoyable. I don't know whether any of my criticisms of the plot are original or just a result of the re edit, but was there an explanation for the Trion sign being on Earth originally? Otherwise not bad by the standards of the time. It would have made a better story without Kamelion and the Master, perhaps. The Master re-appearing ought to be a Big Deal in a way it's not here.
Turlough's departure, for once, feels natural. I'm not sure what is revealed here is consistent with the Black Guardian Trilogy where he was motivated by a promise to return home; and his later attempts to get the Doctor to go there. From what we learn here, he'd be recognised - if not by his personal
notoriety then from the brand. The start of "The Whispering Forest" makes a start at addressing this.
Peri is good - she cottons on to what is going on quickly but not unnaturally and performs
functions other than asking questions and being in peril. There's a clear sense of why she's gone off with the Doctor too...
I'm going to watch the 4-episode version, with commentary to
see how it compares.