Dear Betty -
Yes, this actually happened. And it has been a tale told so often, that there are several versions of the story in existence. Will speak to Pattie Anne (Tom's "official" unofficial historian and general good deed doer) and see what she can come up with for you, to fill in the blanks so to speak, for you and any other interested party.
My best recollection of the event(s) is the two lads went to their school the next day, telling of how Tom and another man, had come to visit and watch that particular episode of "Deadly Assassin," with them: but they were not believed. So either they, or their Da or their Mum wrote to Tom via the BBC requesting a letter from him for some kind of verification of the evenings events. And this was promptly supplied.