I know one person who did the Bournemouth course. He said it's basically a crammer - they know which questions come up all the time, and teach you just enough to be able to answer them. That's how they do it in such a short time. But he said if you wanted to be a safe pilot, just doing the course wasn't nearly enough.
So if you do it, you'll need to somehow make enough time, at some point, to thoroughly learn and understand all the met, nav, and similar stuff which you really need to know!!!