The music in the opening scenes of Ashes and Dust is Boadicea by Enya. Considering the history of Boadicea, especially the fact that she burned 3 Roman cities in Britain to the ground, it is quite an apt selection for this episode.
The episode is quite disturbing. Arsonists are not usually shown so up close and personal with their victims. The haunting music being played while the killer calmly watches his victims burn is chilling.
I found the episode interesting but the opening scenes were far more dramatic than the rest of the programme.
I think the editor was actually cutting to pictures of the 'happy' family rather than the books on the bookcase, showing the contrast between what had been and what was now. Perhaps I'm wrong but I didn't see it as an homage to "Fahrenheit 451".