During the last Liverpool Biennial I took a visiting friend to Liverpool Cathedral. We found the whole of the nave (or Central Space as I think they call it) filled with tables set for dinner, which at first I assumed were of the nature of a work of art, but no - talking to a member of the clergy after evensong (which had been moved to the Lady Chapel), we learned that hiring out the building for dinners is part of Liverpool's attempt to keep entrance to the Cathedral free.
The building may not be medieval, but it is very large indeed, and extremely expensive to heat. The Renaissance Music Group, which has given concerts in the Lady Chapel for as long as anyone can remember, has been told recently that the donation we've always made from concert proceeds will now be a charge, and it will probably be at a level we'll find it difficult to meet.
The Metropolitan Cathedral is fortunate in that the whole of the enormous Lutyens crypt exists underneath it to be made money out of. There have been University exams in it, and CAMRA has held a beer festival there, for years. Still, the Cathedral Concerts Society were alarmed to be told recently that we could no longer assume that we could have concerts in the area known as the Concert Room, as they might want to let that out as well - though I think they've relented a bit on that.