1924 - The Advertising Postcard

The first recorded mass mailing date for the Advertising postcard is August 18th 1924, i.e. just over two weeks after the Expedition returned to Darjeeling.
Later mass mailings continued until October 30th, when the last consignment was despatched from Calcutta.
Based on an acknowledgment in the programme for Noel's film The Epic of Everest, it is possible that the Expedition cards were produced by the leading postcard publisher of the day, Raphael Tuck.

Possibly the earliest recorded use of the advertising postcard - 4th July 1924, from Yatung.
The use of two Everest labels is very rare, as is the possibly unique combination of the Tractor Party cachet and the Base Camp cachet (usually applied in red).
It is also unlikely that any card sent from the expedition travelled further than New Zealand. The fact that it was such a long way for the card to travel perhaps motivated the sender (John Noel we presume) to give it special attention and make it unique.