mtcheer!
I was in Wansbeck House last year. & I promise you, i had an amazing year. Wansbeck is (along with the "house" next door) the only self catered block. &I found the people in it were miles more down to earth than those who were catered (just a generalisation, there were some very nice people in catered blocks, however they tend to be full of 'rahs').
But i really wouldn't worry about Castle Leazes, last year i was exactly the same as you, didnt get either of my choices, sent the Uni letters because i didn't want to stay there, but they said i had no choice, so i ended up going. First off i thought it was horrilbe (because it really isnt the most attractive of places, and it has to be said i'm a bit fussy on accomodation), but after a couple of days, once all your stuffs in your room, its fine, honest.
I loved Wansbeck that much, i was in tears when it came to the end of the year! Haha It was emotional!
What room number are you?
Get to know your corridor, and then the corridors above/below/next to you, and i promise you'll end up with a good set of friends. I've met some of the most amazing group of people, and have so many great memories from my first year! Going to miss it!!