Your landlord is talking as much trash as you can fit in a wheelie bin, Martin! I used to have a student house, and believe me, if anything went wrong, it was fixed IMMEDIATELY. Especially as he's on your Uni's housing list - he's obliged to meet the standards of accommodation that your Uni will set out in guidelines to landlords, believe me.
It's totally wrong that you didn't have hot water, as that's unsanitary for a start. Any leaks should be put right straight away, and if you've got an residual mouldiness, that must be cleaned away, too. Don't hesitate to keep a diary of what you report and when you report (and who you report it to as well). If things get nasty, take photos (like mould, stains, leaks, etc.) and show your Housing Officer. You DO NOT have to put up with being treated like second-rate people, because you are NOT! So report everything in future to your Uni, but be sure to do your bit to avoid any counter-argument, and make sure you keep your rubbish under control.
If the garden is full of brambles, it's up to the landlord also to keep it under control. Students are not expected to buy gardening equipment. If he says YOU should keep it under control, then he has to supply the cutters, etc. But I'm sure in his agreement with the Uni it will say HE is responsible.
Don't be shy about insisting on your right to live in a safe, clean, habitable house, any of you! You wouldn't hire a car knowing it had faulty brakes, so don't hire his house if he won't keep it maintained properly.
All the best, sweetie! Auntie K is with you on this!