I was given a choice of hospitals in the area when I was referred for both gastro and rhumatology and it was great to be able to make a choice based on appointment time or specialty.
I recently moved, same area but out of my GP's catchment and in another main hospital district (Manchester to Salford) and thought I'd have to change my hospital specialists as well as GP.
I checked with rhumatology who said they get patients from all over the country for their specialities and I can stay despite moving which is fantastic news for me as it's a great department.