rogue leader,
I am pretty sure that all the remaining boeing courses are filled so you will be on an airbus course. as previously stated the current airbus bases are berlin, dortmund, paris and gatwick with stansted commencing conversion shortly.
If you can not get your first choice from the start then apply for a base transfer through your base captain and you will be transferred when a place becomes available. Obviously this will be restricted to other airbus bases. When making your second and third choice on application think about the route structure. For instance if you want berlin but that is not available it might be better to be based at gatwick for flights to berlin on your days off rather than say paris. I have assumed here that there are no direct flights between paris and berlin. I am sure you get the gist of my meaning.
I went through training about 15 months ago (on the boeing) and only about half of those on the course were at their first choice of base but by the end of the course (about 8 weeks)we had all been transferred to where we wanted to go. So the lesson is put your transfer request in on day one of joining the company.
Good luck