Possible Clues:

• See 22 Across
• It's hard to work this out as small film reviewed by his companion
• It's hard to work this out, as small film reviewed by his companion
• Message written in secret code
• Stole from helicopter's secret code
• Coded message in one page held by singer
• Secret system
• Reflected on hard image in code
• Message in a code
• Bring up film — the girl’s a nonentity