1: Backblock not all there (3)
2: Fix the oil platform ... (3)
3: Piece of pottery containing drink to make beast tender (9)
4: Strap, though short, has hanger's heart (5)
5: Herb talked about the fourth dimension (5)
8: Pour dripping over tack (5)
9: Many sound prospects for prospectors (5)
11: Throw out faulty nib (3)