deveed411: When applying for NATS, it's not a question of doing so at different places, such as England or Scotland but just to NATS. They have branches all over the UK and it is not possible to restrict your application to certain centers (Without prejudice of being able to be tested at the center you chose, but that's a completely different kettle of fish.). All the centers are united, and do not work independently in what recruitment is concerned.
About RAF: it's not a matter of it being better or worse but about your preferences and likes. If what you mean is if it'll be faster to become and ATC through RAF, it depends on their current situation which I am currently not very aware of.