Hey Maggs! Very exciting decision.
Now, there are a few options open to you.
The BMW course, if it is the one I am thinking of, is an off-road riding course. That's a brilliant option and a pretty steep learning curve (but they're the best kind!).
Honda, Yamaha and KTM run similar courses. KTM does a womens only course a few times a year, if you think the boys tend to go too bananas
I found that the off-road course was something that I opted for to improve my riding and to prepare me for the rough stuff, after I had my license.
I got my license in a couple of months by first doing my CBT (compulsory basic training - I think that's what it is) and then doing my full license over 4 days, in London.
I had never riden before (I don't count the couple of goes on a boyfriends bike that amounted to covering about 100m). The guys teaching the course were very good - completely comfortable teaching women, and great with the basics for everyone (some of the blokes battled far more than I did!).
As soon as I had done the one day CBT, I contacted the DVLA to sit their multiple choice exam that you have to have before doing your license, and then put my name on the list for the very next Full License course.
There is a Direct Access option, which is a quick route to a full license, if you are over 25.
The instructors on my course had had a group of motorX riders on one course and had found it difficult to change their off-road (leg-out-around-corners)riding styles so that they could adopt the street riding behaviours that the examiners would pass.
Depending on how keen you are to be 'legal', it may be worth considering the CBT before an off-road course?
(if of course I have the right end of things with the BMW course in wales that you mentioned! And naturally, this is only a thought - try it on and see if it fits or not)