1: Principal on top of leafy tree (5)
2: Mineral springs start to moderate involuntary muscular contraction (5)
3: Difficult newspaper or novel (4,5)
4: Ran into a section of the time-table (3)
5: Looks like an eyesore, sounds like an eyesore (3)
9: I had been at the front, and retired (5)
10: De Bergerac hugged bird on return (5)
11: Frost to cover the cake (3)