I wonder how many are in the UK. It doesn't seem as common to keep birds over here. In fact, the pet shop I used to work at stopped selling all birds. They used to sell finches, canaries, budgies, rosellas, cockatiels.., and the occasional african grey (which is how I first came across them and gained interest in them). We also had an eclectus in once... though that was from another store who hadn't cared for him properly so we looked after him, fed him properly and then sold him once he was in a better condition and was ready to move to his (hopefully) forever home. I still have a soft spot for electus parrots to this day because of him.
Years ago they decided that birds weren't as popular as other pets so stopped selling them and drastically reduced their bird products. They only sell a few bits and pieces for small birds nowadays.
None of my friends or family keep birds of any variety and I don't often hear about people keeping birds in my local area.