1: One who administers drug treatments puts me in band at Hat Head (9)
8: Common thread uniting New York and half of London (5)
9: Sounds like Brazilian soccer player may make a good fisher (7)
13: In lieu, make a change for blood disorder (9)
14: Characters producing exit with cross? (9)
16: Ball mislaid? Caned (5)
17: Frequently held back by internet formalities (5)
18: You say the apartment you let someone use is having a problem with gas? (9)
20: Who applies pitch to a snake-rope? (9)
21: Jacket flap with label's centerpiece inverted? (5)
23: It's over, over, over, kept apart by past payment (7)
24: Notable piece of animation by English bishop (5)
26: Weirdos drop feet-first in pools (5)
27: Doctor singes off top of sore and bandages (9)