Related Clues:
- Christmas cards? Mum has one left
- Protection for old soldier, Irishman retreating
- Miles:millilitres, in which there's one:one correspondence
- Audible testosterone-fuelled letters
- Neeson flick of 2010 (with "The")
- Contents of some drop boxes
- Almost-daily delivery
- Cover of knight?
- Letter carrier's delivery
- Post office supply
- Bills in a box
- Large number have a complaint when it goes astray
- First-string athletic group
- Armour; posted items
- There are more than four letters in this