Possible Clues:

• Army musician, possibly, with sergeant-major in bar
• Outlaw damns foreign soldier banging his drum
• Days in bars with chap being player
• Military musician
• Days in bars with chap, brass player perhaps
• Musician and detective on island propping up bar
• Musician rings any number to get mother admitted
• Outlaw damns travelling soldier banging his drum
• A new key used by sergeant major to go into bar with musician
• Sergeant-major wearing neckerchief, not a musician