IIRC the first high-altitude Ju-86s were based on Crete. The Spit in question looks like one of the modified high-altitude jobbies, either a Mk.VI, VII or IX. Probably removed the machine guns and kept only the two Hispano 20mms for weight saving too.
We already know that the aircraft is a Spit and the other one is a Ju-86. Pilots' names were probably Oberfeldwebel Horst Goetz in the Ju and Pilot Officer Prince Emanuel Galitzine in the Spit.
This after some digging:
"The Mk IX version of the Spitfire, which had just entered service, was fitted with the new Merlin 61 and that possessed two-stage supercharging. With this refinement, the Merlin delivered 600hp at 40,000ft, substantially more than was possible at such an altitude from its predecessor. To combat the high-altitude Junkers, a special unit was formed with modified Mk IXs. One of the pilots selected was Pilot Officer Prince Emanuel Galitzine who had been born in Russia in 1918, brought to England the following year and who had lived here since. He now gives us his recollections of the operations to combat the high-flying German bombers.
At the end of August 1942 I was flying Spitfire IXs with 611 Sqn at Redhill when, following a medical examination, I was pronounced fit for very high altitude operations and sent to join the Special Service Flight which was then forming at Northolt. On arrival there, I learnt the purpose of the new unit. During the previous couple of weeks the Germans had been sending in single Junkers bombers at altitudes above 40,000ft to attack targets in southern England. Conventional fighter units had found these high-flying raiders impossible to catch, with medically selected and specially trained pilots flying modified Spitfire IXs, we hoped to do better. There were 6 of us in the Special Service Flight which was under the command of Flt Lt Jimmy Nelson, an American ex-Eagle Squadron pilot.
Training for the new role began immediately. First of all we were put on a special diet which included plenty of sweets, chocolate, eggs and bacon, fresh orange juice and other things which at that time were either strictly rationed or else unobtainable. There is now some doubt regarding the effectiveness of this diet in improving our performance at high altitude but it certainly did a lot for our morale and increased our standing with the girls.
As part of our training we were sent to Farnborough where we underwent tests in the decompression chamber and had a short course of lectures from the doctors there. To conserve our strength and delay the onset of oxygen shortage at high altitude, we were enjoined to make all our movements slowly and deliberately. Everything had to be done in an icy calm manner.
At the end of the first week in September the Flight received the first of our Spitfire IXs which had been modified for very high altitude operations. The aircraft, serial BF273, had been lightened in almost every way possible. A lighter wooden propeller had been substituted for the normal metal one, all of the armour had been removed as had the four machine guns, leaving an armament of only 2 Hispano 20mm cannons. The aircraft was finished in a special lightweight finish, which gave it a colour rather like Cambridge blue and all equipment not strictly necessary for high altitude fighting was removed. It had the normal wingtips. A pressure cabin would have been very nice but the HF VII, essentially a Mk IX with a pressure cabin, was not yet read for operations.
On September 10th I made my first flight in the modified Spitfire IX and found it absolutely delightful to handle. During the war I flew 11 versions of the Spitfire and this was far and away the best. The 450lb reduction in weight was immediately noticeable once airborne and with the Merlin 61 she had plenty of power and was very lively. I made a second flight that day to test the cannons, during which I took her up to 43,000ft. I stayed above 40,000ft for some time and found it quite exhilarating, it was a beautiful day and I could see along the coast of England from Dover to Plymouth and almost the whole of the northern coast of France as far as Belgium and Holland.
During this flight I wore an electrically heated flying suit which kept me warm and comfortable.
On September 12th I made my second high altitude flight and this time it was in earnest. That morning, it had been my turn to wait at readiness and at 09.27hrs I was scrambled to meet an aircraft being watched on radar climbing to height over France; it looked suspiciously like another one of the high-flying raiders.
Climbing away at full throttle, the Spitfire went up like a lift but there was a long way to go – 40,000ft is about 7.5 miles up. I climbed in a wide spiral over Northolt to 15,000ft then the ground controller informed me that the incoming aircraft was over mid-Channel and heading towards the Portsmouth area, I was ordered onto a south-westerly heading to cut him off. After several course corrections I finally caught sight of the enemy aircraft as it was flying up the Solent, I was at about 40,000ft and he was slightly higher and out to starboard. I continued my climb and headed after him, closing in until I could make out the outline of a Junkers 86, By then, I was about half a mile from him and we were both at 42,000ft to the north of Southampton.
The German crew had obviously seen me, because I saw the bomb jettison, the aircraft nose go up to gain altitude and turn for home. My Spitfire had plenty of performance in hand, however. I jettisoned my 30-gal slipper tank and had little difficulty in following him in the climb and getting about 200ft above the bomber. At this stage I kept reminding myself “Take it easy, conserve your strength, keep icy calm”. The grey-blue Junkers seemed enormous and it trailed a long, curling condensation trail. It reminded me of a film I had once seen of an aerial view of an ocean liner ploughing through a calm sea and leaving a wake.
I positioned myself for an attack and dived to about 200yds astern of him, where I opened up with a 3-second burst. At the end of the burst my port cannon jammed and the Spitfire slewed round to starboard, then, as I passed through his slipstream, my canopy misted over. It took about a minute to clear completely, during which time I climbed back into position for the next attack. When I next saw the Junkers he was heading southwards, trying to escape out to sea. I knew I had to get right in close behind him if I was to stand any chance of scoring hits, because it would be difficult to hold the Spitfire straight when the starboard cannon fired and she went into a yaw. Again, I dived to attack but when I was about a hundred yards away the bomber made a surprisingly tight turn to starboard. I opened fire but the Spitfire went into a yaw and fell out of the sky, I broke off the attack, turned outside him and climbed back to 44,000ft.
I carried out two further attacks on the Junkers. On each of them my Spitfire yawed and fell out of the sky whenever I opened fire with my remaining cannon, and my canopy misted over whenever I passed through his slipstream. By the end of the fourth attack the action had lasted about 45 minutes. My engine had been running at full throttle for an hour and a quarter and my fuel was beginning to run low. So when the bomber descended into a patch of mist I did not attempt to follow. Instead I broke away and turned north east for home. How I cursed that jammed cannon, had it not failed, I would certainly have shot down the Ju86. As I neared the coast it became clear that I did not have sufficient fuel to reach Northolt, so I landed at Tangmere to refuel.”
In all my years I've never seen the like. It has to be more than a hundred sea miles and he brings us up on his tail. That's seamanship, Mr. Pullings. My God, that's seamanship!