I haven't been in the simulator but I do know people that have and say they enjoyed it.
That said, I had a one to one lesson in a light aircraft as a birthday gift and I'm sure it was a lot less than £320. I had a terrific experience, really learned a lot and would thoroughly recommend. I can't imagine a simulator would be more fun for just the experience of flying. If you are only really interested in the workings of a 747, then maybe...