We have servers colocated in Caladan. The colo company is using the University's facilities. Check out their prices. They offer much cheaper bandwidth prices, bandwidth does start at £6 but it get's cheaper, the more you buy/use.
So comparing like-for-like (as anyone who's ever watched QVC will know this is essential) is 10Gb with your guys £60, compared to our £25?
By using the university's facilities, do you just mean they are in their computer centre or they actually connect your servers over JANET? I'm pretty sure you can't use JANET for any commercial traffic, so be careful if that's the case.