Until article 50 of the Lisbon Treaty is invoked nothing will change. When it will be invoked, there will a 2-year process to re-negotiate everything, but I guess the Great Britain won't pull out of EASA.
If Great Britain doesn't want to accept freedom of movement, then I have no idea what could happen to new aspiring British pilots with their options limited to Great Britain (or the UK if it will still exist).
Current British pilots working and living in Europe won't be sent back home.