Possible Clues:

• Dancing colonialist's rhythmic movement
• Swaying, rocking action so, bilious on board
• Outstanding Liverpudlian singer madly into swing
• Colonialist abroad going back and forth
• Movement of pendulum affected at collision
• Cycle — 5 down (anag)
• Colonialist playing swing
• Rhythmic swinging to and fro
• Presumably, only upright text stradding line, nothing inverted or swinging
• Movement to and fro