This is nice; I'm moving to a student house for year two of my university course... Really not giving me confidence in the house we chose! I kid, but anyway...
You may want to post this on The Student Room forums as well; since it's full of people who have probably had similar experience with these kinds of problems. I don't know what it is about student housing landlords, but they seem to think that because you're a student they can rip you off as much as they like without any concequences.
As long as you, yourselves are not breaking any of the contract agreements during your time in the house, file as many complaints and inspections as possible; they can't kick you out for it. Document everything that happens, which I'm sure you already have; including times of day, names of people who came and exact problems. It'll make the whole case stand up better. Receipts for stuff you replaced yourselves might come in handy, too. You need to make the most out of this sorry situation.