Apply next year or transfer?Watch
Also, what would my chances be of transfering to a good Uni after my first year, if i'm currently at an average Uni?
There really is no point starting a course if you know you won't enjoy it. You could transfer, but there is no guarantee the universities you want to go to would accept you - not all universities accept transfer students and those that do can afford to be very picky. It would be far less risky to re-apply for the 2016 entry. There is a FAQ in this thread, have a read through.
Otherwise gap year and apply for 2016. Going into 2nd year at a new uni, where you don't know anyone, where they teach/grade things differently etc wouldn't be wise since year 2 actually counts. Just reapply if you don't get anything sorted this year.
I'd reiterate the advice above about having a look in Clearing. Or if that doesn't get you the sort of course you want a gap year is preferable to starting a degree with no intention of completing.