Aha. This is going back a while for me. Many years ago when I lived in the UK I used to know an old chap who worked in a photo archive and knowing my interest in aviation would often show me pictures of aeroplanes he had come across. I remember he showed me one of a Spitfire on floats surrounded by some guys in tropical dress; i.e. just shorts, no shirts. It was taken somewhere in Egypt, possibly Great Bitter Lake, where the three Spitfire Vs that I mentioned earlier were tested. He was given the photo by an old guy he knew and had said he was one of the guys in the picture and he wanted me to tell him if I had any knowledge of Spitfires on floats. I said I could look it up and found a few references in books for him. I refered him to "Spitfire the History" by Morgan and Shacklady, which gives information about how many aircraft were converted and where they were sent in the Med. One thing the book doesn't mention is what the guy who gave the photo to the old feller I knew had said about the photo.
He and his colleagues were enlarging an opening aft of the cockpit in the side of the Spitfire large enough to enable a person to be carried aboard. He was not told that they had to fit a person aboard the Spitfire, just that it was to be done. Rumours certainly flew about regarding flights to Yugoslavia with the Spitfire landing on lakes in the country, but nothing concrete was ever told to him whilst he was in the RAF. He never did find out exactly why the hole was cut out, but years later he came across Churchill's memoirs, which mentions a mission to Yugoslavia in support of guerilla activity against the Germans led by Marshal Tito, by a prominent British officer with Foreign Office training. This chap was to visit Yugoslavia clandestinely to establish links with Yugo partisans in an attempt to establish which party would rule the country after the Germans had been extricated and whether they would be friendly to the British or not. How the chap was to get to and from Yugoslavia was not given in Churchill's memoirs.
When this guy read this he thought that it wasn't entirely implauseable that a man of very small stature could squeeze into the cavity behind the cockpit of a Spitfire for a round trip of nearly 2,000 miles, but it seemed far fetched. The Spitfires that were sent were to engage in combat with German transport aircraft and were to be refuelled by submarine at forward operating areas, which makes the flights to Yugoslavia from Egypt more achieveable with the Spitfire's range. Many years later the chap went to the former Republic of Yugoslavia for a holiday in the lakes area. Whilst there he decided to ask around if anyone remembered the area from the war. He met a few locals, including a village priest who did remember seeing float planes landing on the lakes, but didn't know what it was about, nor did he enquire, not that a Yugoslav priest could tell a Spitfire from another type of floatplane.
Anyway. I've recounted this story from an article that I have stashed away that was written for a local community magazine in Scotland, where I used to live. Perhaps something will be released to the public that might put all this into perspective, but whether there is a link between this guy's activities during the war and Yugoslav partisans or not, it certainly makes a fascinating story!