Yes it is currently BRAL and based where they need crew, so it could be, Isle of Man, MAN, CWL, or any of their other bases.
When you join Airtours it is a matter of training slots available, where they need crew and what aircraft you are type rated on that will determine your base.
You are asked for your preference but as with all things in aviation, the final allocation will be revealed when you arrive.
Good luck with the application.
