Possible Clues:

• Known by few
• Mysterious coteries dispersed
• Secret, like Annie Besant's faith?
• Rumours offstage from Michael Frayn
• Recite so strangely in secret
• Indecipherable
• It's mysterious how the boy can have got broken toes
• Mysterious man, holding up boozer, is after key
• Secret I let out about the band that's known to few
• Like coteries, perhaps?