This one lacked any depth for me. Both the characters and the storyline failed to inspire or intrigue. I think it was meant to be a romance, but there was little to none of that. I think the MC and his lady friend kissed twice. Maybe three times and held hands... If it was supposed to be a history makeover, I guess it sort of did that. As far as SF/F, just no. Other than taking a couple of modern people and throwing them back in time, with one of them holding a service pistol (I believe members of MI 5 don't carry guns as a general rule, so why did this Callum guy have one?) and another toting a modern recurve bow, there was nothing.
Spoiler to follow.
I was most disappointed with the ending. I don't know or care how things happened back in the day, but the story was building toward a final epic battle. Then, when all these hot-head nobles came together for the big clash, they all decided to sit down and have a nice brunch instead. Bleh.