Related Clues:
- Headdresses
- Haberdashery buys
- They may be tipped in acknowledgment
- Busby and derby
- Milliner's inventory
- Bonnet, perhaps, hides top set of wheels
- Capital investment
- Hats, etc
- Hat(s)
- 'Porkpie' and 'pillbox' attire
- They may be passed or tipped
- Hats, hoods and helmets
- Principal stuff, like a mortar board perhaps
- Berets and sombreros
- Roles, in metaphor