Related Clues:

• One must be on the lookout for one in mail
• Letters to be sent from the sentry?
• Not letters received by those on watch
• Letter sent to a remote station?
• Letters being sent to distant branch
• Letters processed, but settlement far off
• Correspondence published in the 'Gay Times'? It's the end of civilisation!
• Letters awaiting despatch to a colonial settlement
• Place for censored correspondence?
• Dated mail for the frontier
• Letters dealt with, you might say, in remote settlement
• Outlying settlement
• Place of group some way from base
• Military camp in the back of beyond is not in support
• Send letters, in a manner of speaking, as it's very isolated here