The photo was archived more than two decades ago and recent efforts to research the other people depicted has met only partial success.
It has since become clear that one person was Douglas Arnold, an extraordinary figure from the Conwy- Valley who was one of the SAS 'originals.'
While his cycling activities were legendary - he often cycled to SAS reunions in London - little was known about his war-time exploits.
Besides serving with the Special Air Service in North Africa and northwest Europe, he was an accomplished escape artist, twice breaking out from prisoner of war camps.
Friends recalled how he always signed Christmas cards with 'May you always walk in the sun' - and his service record suggests the reason why.
The photo, taken at a stone walling event, was filed away more than 20 years ago by the North Wales branch of the Dry Stone Walling Association (DSWA).
Coming across it a few years ago, in a bare envelope, was its former secretary Sean Adcock, who resolved to find out who were pictured meeting the future king.
He suspects the event was in the mid to late 1980s. "I vaguely recognised the chap on the right who was quite a character," said Sean, a master stone waller from Penisarwaen, Gwynedd.
"I remembered him cycling to branch meetings and events in all weathers in the early 1990s - he'd cycle from his home in Tal y Cafn in the Conwy Valley to places like Cerrigydrudion and Porthmadog. After the meetings ended at 9.30pm or 10pm, he'd then ride back home again!
image [https://cdn.magzter.com/1583575389/1735624624/articles/RTjZup5G3lQuBmdptj5k36/1773131151.jpg]
"But couldn't remember his name. I had a vague idea he had been a Commando in the Second World War, but I knew little else. I managed to find his name from a short obituary in a branch newsletter from 1997, which confirmed his commando connection but little else. I then stumbled across some information on a Commando Veterans blog."
Doug, born in Liverpool in 1919, served with 7th Commando on Crete when it fell to the Germans. While the rest of the British forces surrendered, he led a daring escape of 14 soldiers in a motorboat. Three men died on board before they reached Sidi Barani, Egypt, some 1,155km away.
While recovering in an allied hospital, he was approached by David Stirling. The founder of the Special AirService had heard of his escape and wanted him for his new outfit, as documented in the recent BBC TV series 'Rogue Heroes.'
Doug thus became one of the 66 SAS 'originals' who took part in the regiment's first raid. The ill-fated 'Operation Squatter' on November 16, 1941, targeted the Axis airfields of Ghazala and Timimi in Libya. Most of those taking part were either captured or killed - only 22 retur...