We visited St Paul’s as a family about 18 years ago. Having paid a considerable sum to get in, we were suddenly ushered out after about half an hour - I think they were going to hold a service there. The ushers were quite rude and abrupt!
I did think that £18 was quite steep for York Minster last month, but to be fair, they had volunteers there who were more than eager to tell us more about the window restoration project and the museum in the crypt was well laid out and very informative.