Smauggie,
The stamp was Great Britain's First airmail. Issued in Self-Adhesive booklets of 4 with regular gummed airmail etiquettes, in the year 2004 !
All of Britains airmail stamps since then have been similarly issued.
ST.KILDA
Uninhabited sine 1930, here is a sad and poignant story about the Island.Even stamps get a mention, albeit cruelly !
http://www.powell-pressburger.org/R...Edge_03.htmlHere are a few Modern day National Trust Cinderellas, the made-for-Collectors variety. I hate to call them bogus..........

Londonbus1