This is an attractive, rare piece of British military postal history! It was sent by a British soldier(most likely with the 12th Company, Royal Garrison Artillery) from Heraklion(RARE!), Crete, Greece, on February 11, 1908! He was on a military transport that was moving various units of troops to Malta and Crete(3rd Rifles), and picking up a unit, the Inniskilling Fusiliers(in Crete)! The addressee was a C.S. Major Scott, of 12th Company, Royal Garrison Artillery, Landguard Fort, Essex, England.
To continue, the red, 1-Penny GB issue is in very fine condition! The CDS from the Heraklion P.O. was first applied, and the London F.S. Machine cancel(RARE!) added after the mail had arrived there on March 7, 1908!
Lastly, as for the post card, itself, it's in fine-very fine condition! It's pretty clean. There is very little wear and tear on it. The images on the front of the post card from Gibraltar are still quite clear. Simply put, this is a really neat, uncommon piece of British military postal history!