First things first, I don't wish to speak ill of the dead, but did Mr O Donnell ever hear anyone actually speak in the english language?
As for Misha Barton, IMDB says she's had a career spanning more than 20 years, but I have never actually seen her in anything, and I have to say, I thought she was probably Canadian, especially with the cut glass English Accent she affected!
This film is set in the 1930's, a shop girl, even a florist, would not have the accent Ms Barton adopts, she is so posh our own Queen, God Bless her, never sounded as posh, and frankly with the accent and Miranda's dreadful and laughable dialogue I so much wanted the reason she didn't have her return ticket was because she would be bumped off in minutes of arriving on the island.
As for the rest of the plot, there are so many holes to be plugged, I don't have time or the inclination to go through them, I will point out one glaringly obvious hole, this occurred during the first (alleged) murder. As anyone knows, in the case of a murder or even an injury, the Doctor at the scene is the first into action, Armstrong didn't bother to check for sign of life. In fact, he was the one who ran off to get help! Totally implausible! Obviously he would have known Kane wasn't dead, so why have him at the scene, the writers could have had him taking a very long cold shower, as he so wanted to sleep with Ms Blanco...
I leave you the viewer to draw your own conclusions, just be prepared for the grating accent and acting of Ms Barton.