We are having fun at my expense this morning aren't we !
I never noticed the US connection before. I will have to write to Londopn Transport.
David, your postcard most likely went by ship !
Your Parents uesd a Universal Mail stamp which is available from Tourist shops in both London and other major cities in the UK. The stamps are only available for use on International Letters or Postcards and NOT inland mail [I tried it, and sure enough it doesn't work !]
The Company is New Zealand-based.
The stamps are printed by Enschede of Holland, Self-Adhesive in strips of 5. Many different designs but with Flags !
The stamp with the Routemaster is particularly impressive !
Those items sent to me with Air mail etiquettes arrived quite quickly, those without took anything up to 6 weeks . My enquiries at the Port here in Ashdod and with the Postal service leads me to believe they came by ship. But there are no markings to say so, not that there should be.
In the UK, items bearing these stamps can be posted in the RM post boxes. They are then sent to the Universal Mail Office in London for onward despatch. This latter part is still a bit of a mystery but I do have a contact within the company whom I hope can shed further light on the service.
International Letter stamp , Flag and Printers Imprint only.
Mint strips and backing card.
Londonbus1....gets everywhere ! [usually late]