On the minus side, I think the programme is flawed by an attempt to do two separate things, to investigate the 'real' Helen and to examine Helen as a symbol, and blurring the distinction between the two. Hughes talks about her conviction that behind the legendary Helen lies a real Bronze Age queen. She offers no evidence to prove this, because, as she admits, there is none. This doesn't mean that she's wrong, of course. Mythology often coalesces around real individuals (just look at the American West for an example where we can still trace the historical personages concerned), and I am not unhappy to imagine that there might have been a 'real' Helen, or a 'real' Agamemnon, etc. But, as with King Arthur, I wouldn't go much further than that. It's okay to look at what we know of the lives of women in the Mycenaean period. It's okay to look at how archaeologically-attested details turn up in the later legend. It's okay to look at how the political reality revealed by Hittite documents is partially preserved in Homer. It's okay to look at how Helen developed as a symbol for later Greeks (though here Hughes cheats a little, saying at the beginning that we must strip away later interpretations, but being happy to use material from later sources when it suits her). The moment, however, that you begin to retroject details from the legendary Helen to tell the story of the 'real' queen, you're in trouble. The legends have passed through many hands even before they are first written down. Each retelling will add something new, and by the time it gets to Homer, much of the story will be made up. Homer will make stuff up himself - it's what writers do. This isn't to say that some of what we find in the legends of Helen doesn't go back to a real person's life, but to say that it is irrecoverable what is real and what is made up.
Take, for instance, the eloping of Helen and Paris. Now, it may very well be the case that had a foreign prince arrived at Sparta as a xenos, a 'guest-friend', then it would be a very serious breach of etiquette and protocol to run off with the king's wife, and that this could have very serious consequences. Hughes points to records of two Hittite vassal states coming close to war over a princess. But Helen and Paris is also a great romantic story, and simply showing that it is plausible that states might go to war over a woman doesn't show that this story is true.
This programme took the most recent developments in archaeology and Hittitology (which seems to have moved on considerably since I last had any idea what was going on) and weds it to a very traditional approach, the search for the 'truth' behind the legend.