Especially for an episode that didn’t really have the Doctor in it. In Hartnell’s day, he would take a week or two off here and there and nobody would really notice. None of his successors managed to get away with it to the same extent though.
By truly bizarre coincidence, I banged in my ancient videocassette of Frontier In Space this afternoon, and in the first episode there is a 26th century newsreader played by Louis Mahoney. And there he is again this evening, playing the older version of Billy. (It would be a truly brilliant example of synchronicity if he had appeared in a Doctor Who episode first broadcast in 1969, but it was 1973. And, I see on further research, also 1975.)
Edited to add:
Even the great Robert Holmes had an off day now and then. But Steven Moffat is now definitely the greatest Doctor Who writer of all time. Each of his stories has been outstanding.
I say it again. That was one of the best episodes ever.
I believe Jones’s use of “professional” refers to a classification, rather than his subjective view of its merit. Similar to the idea that a book is not a “mass market paperback” if it doesn’t conform to the physical dimensions of the industry’s definition of a mass market paperback, and has nothing to do with whether said paperback book was released into the mass market.
In that sense, had Beautiful Monsters been issued by Virgin or S&S without a single change, he would have called it “professional”.
That’s my take, at any rate, based on my limited conversations with Mr Jones.