I went to conventions at Sheffield Hillsborough, Leeds, and Sheffield Don Valley - and I think at Hillsborough we were sitting on the terraces :( with some other mums and babies and there were buggies (this was early 80's).
At Leeds we had to go up steps to get to the stands and there was a buggy zone - not a *ban* per se but it's either leave your buggy there or drag it up flights of stone steps and have to keep it in the aisle, so common sense really, but not common sense with the choice of location - football stadiums are not designed for babies and prams! At Leeds the buggy zone was inside on the concourse and there was a bit of seating so some mums went and put their babies to sleep there and sat and could still hear the session - but mostly the buggies and prams were just stacked.
I think at Don Valley they were in an indoor training track.