Nah, its about 2 miles away. Though if you walk from halls, you'll walk past a campus of theirs which always seems to be empty. I went on an exploration of their main campus last term, it really is crap, there were pockets of urban wasteland right in the middle of it haha.
The rivalry is there for some people, personally I think it's stupid and don't care, a little banters fine, but there's a facebook group called 'De Montfort is not an actual university' and the argument on it really is retarded on both sides.
I was never really involved in any interhall pranks, except when it was snowing and we infiltrated Stamford and threw snowballs at unsuspecting Stamfordians heh.