GBZ, I was going to comment from what my then boss told be many years ago, however your second quote covers all the points he made.
The conditions in which the prisoners were kept was similar to the conditions that the Turkish troops enjoyed at home. Furthermore the Koreans did not have as many Turkish linguists.
There was a particularly vivid film, I think the princple, playing a British Army Cpl was Victor Madden (or something like that). The film might have been made by the Army Film Unit and the message was solidarity in hardship. One of the POWs was an outsider and therefore picked on by the Koreans. He was brought back into the fold and they all resisted successfully.
The isolation that the Iranians practised served to cut out one of two of the prisoners. When they were all reunited for the photoshoots that rather upset that ploy.