I'm always dubious when a Hollywood "it" child of famous parent(s) gets cast in UK films with period costume and nationalist story lines. In this case, Kate Hudson is the typical casting decision that Hollywood suits would think suitable for a male-dominated commercial film venture. Perhaps her parents contributed to the production cost with the rider that their kid get a staring part, or, the producers had no idea the kind of storyline involved needed a female actor who could actually act. Being cute and blonde got Goldie Hawn a long way in Hollywood and it seems to be getting her minimally talented and not so cute daughter equal milage. Sadly for the film going audience, we waste our money and time on films that are marred by Hudson's presence on screen.
If Ewan McGregor were a lollipop I'd be a diabetic strumpet

She was VERY miscast

I think they should have used British actors to play all of the British roles. I like HL and WB very much, but WB is better on the other side of the ocean. Heath did a fairly good job (at least he has an accent in real life, although not a British one), but he just looks like a punk in a lot of this movie. I agree with the guy who said his hair was bad, and I found it very distracting.
Kate was plain awful, terrible accent, terrible looks (in this), terrible depth (none), offering no reason whatsoever to have these two guys in love with her. She should stick to shallow American roles, where she can play a cutie pie blonde modern person. Maybe they should have pulled her buddy Isabelle (Lucy Gordon) out of the five-second role she had, to play Ethne. At least she's British.