talking to today. They said the only place that could handle 400-500 delegates is the Reynolds Building, which is on Sackville Street, not
They did also suggest that Fallowfield Road is a possibility, although it was described to me as "being a bit run-down" :-). I'm consulting
FYI, I've been to one conference using the Reynolds building - annual OUSA conference - and we used accommodation a very short walk away. Good facilities generally, although quality of the food in their refectory left something to be desired I felt!
I've also used the student halls at Fallowfield twice for a convention (last year and in 2000, iirc). Good on the rooms and break-out facilities (and, tbh, it isn't as bad as "run-down" suggests) though I don't recall any space large enough for 400-500 at a time, but that might just be because we only needed a space for 200 or so. Fallowfield could easily accomodate any number who might turn up though and both those uses were rooms for seven days at the flat rate
Alison