British scientists had the earliest opportunity to see major parts of V-2 - notably all parts of guidance system.
Below is fragment of memoir of the Flying Officer K. Szrajer:
"One of the biggest achievements by the Polish Underground Forces in World War II was its operation called “Trzeci Most” (Third Bridge). It was carried out as a joint operation with the British Special Operations Executive – the SOE, which gave it a cryptonym “Wildhorn III”. Its objective was to smuggle pieces of the V-2 rocket – the German wunderwaffe – out of occupied Poland, so the British could study them. At this stage, British still did not know what capability the rocket might had and what to expect from its use against Britain. After their primary site at Peenemünde was bombed, the Germans established a launching site at Blizna, Poland, from where they continued to test V-2. Poles set up a chain post of small units responsible for beating the Germans to the sites of impacts of the tested rockets. One of those V-2 had landed in a marsh close to the bank of the River Bug near village of Sarnaki, some 80 miles east of Warsaw. Members of the Polish Resistance found it before Germans did, and since it was sticking out, pushed it deep into water making it invisible. Later they recovered it and a team of Polish engineers, under Jerzy Chmielewski, dismantled most vital parts. They were spirited out of occupied Poland by means of air transport. Kazimierz Szrajer reminiscences:
These events took place in July 1944, toward the end of my operational tour on Halifaxes. I was with the 1586 Flight stationed at Brindisi, Italy. I was called by our squadron leader who informed me that I was assigned to the British crew of a Dakota for a assignment to Poland. We were to land there for a pickup. He advised me to be physically and morally prepared for this flight. I felt deeply honoured and for a next few days I was excited, impatiently waiting for my assignment.
Finally, in a morning of July 25th, I was informed that the flight would take place that night. The plane was to land at Brindisi to pick me up. I suddenly realized that I never flew that type of aircraft, and started be a little apprehensive. My commander assured me that I’ll do just fine and that the British pilot would brief me about plane’s systems and a take-off procedure. That exactly what happened. I took F/Lt Culliford , a New Zealander, about five minutes to introduce me to Dakota. After referring me to instruments, fuel and undercarriage system, he made a fully qualified co-pilot. Our plane had two extra tanks installed in the fuselage, what extended its range significantly and allowed us to stay airborne for at least 13 hours. Our crew consisted of: F/Lt S.C. Culliford (pilot), F/O K. Szrajer (co-pilot and translator), F/O J.P. Williams (navigator) and F/Sgt J. Appleby (wireless operator). It was to be my twentieth flight to the occupied Poland.
We took off from Brindisi at 7:30 p.m. escorted by a Polish Liberator. It was mostly for our psychical comfort, since both planes were easy target for German fighters. On board we had some equipment and four passengers. Not only the common sense but also strict regulations prohibited us from knowing whom they were. After the war I learned from different sources that our passengers were: Kazimierz Bilski, Jan Nowak, Leszek Starzynski and Boguslaw Wolniak.
During crossing of the Yugoslavian coast nightfall came. Until that moment I had a radio contact with our escort, which took its own course. Ours led through Yugoslavia, Hungary and Czechoslovakia. Over Hungary we saw AA in action, but far from us and apparently stimulated by somebody else. Our orientation point for landing was the outlet of the River Dunajec to the River Vistula. We reached it according to plan, right on time. Down there they waited for us, and after signals exchange, the lights appeared on four corners of the landing strip. Pilot made two attempts before putting down the plane. Right after we stoped I opened the door to established contact with the receiving party. I was welcomed by por. Wlodzimierz Gedymin who commanded on the ground. Our passengers left, the equipment was unloaded and took five new passengers. They were: T. Arciszewski, J. Retinger, J. Chmielewski, T. Chciuk and C. Micinski. Jerzy Chmielewski was in possession of the V-2 parts and written report on them. He was responsible for the watch on Blizna.
After only several minutes on the ground we got ready to take off. It turned out that the field was oozy. Our Dakota was stuck in the mud. I immediately realized my situation: I was on a Polish soil and I could join the Polish Resistance and in few days meet my family and friends. The Polish officer was asking me a lot of questions about certain people, Polish units, etc. while there was no time to waste. We franticly tried to free the aircraft, all in vain. We were running out of time and we discussed burning the plane. Finally, after an hour and five minutes on a ground, we succeeded and took off for home.
We still had a big problem on our hands. In our desperation to budge the aircraft we severed their hydraulic hoses to eliminate the possibility of the wheels’ locked breaks. This prevented us from lifting up the undercarriage. Flying with the wheels down created a drag what threatened with running out of fuel before reaching our base. We filled the hydraulic tank with whatever fluid we could get: water, thermos tea, whatever. By the time we passed the Tatra Mountains, we had the wheels up. Then I went to see to our passengers and instruct them about parachute harness in case of need. Back in the cockpit I took over the controls. It was a beautiful, starry and calm night and we all calmed down, calculating that after three hours of flight we’ll back home and relatively safe. I reflected on the group of people we left in behind us, who already for five years fought with the hated occupant, and who put a lot of effort into the “Third Bridge”. Our successful flight back to Allied territory with the parts of V-2 was their triumph.

1944. Polish pilots of the 1586 Flight in Brindisi, Italy. Second from stands F/O Szrajer.

Kazimierz Szrajer being decorated with Cross of Valour.
By pure luck, this mission was almost scrapped by the last minute, when unexpectedly, a day before the operation, the Germans set up an outpost with two FW190s fighters on the very strip designated for Dakota to land. Fortunately, they left the same day and Resistance was able to prepare everything on time. Jerzy Chmielewski who brought V-2 parts with him to England could speak no English and categorically refused to give them away until he had an order from only two Polish officers on British soil he knew able to issue it. The pole set on his treasure and threatened with a knife anybody who made an attempt to have a look on it. The stalemate lasted for several hours before he obtained the authority to relinquish his collection. Undoubtedly, it was yet another vital contribution of the Polish nation to the Allies war effort."
Here a few links with interesting info:
http://www.biocrawler.com/encyclopedia/V-2
http://www.astronautix.com/lvs/v2.htm - Really good!
http://www.v2rocket.com/
http://pedia.nodeworks.com/B/BL/BLI/Blizna
http://www.project1947.com/gr/grchron1.htmhttp://www.project1947.com/gr/grchron1.htm
http://reformed-theology.org/html/books/best_enemy/chapter_06.htm
Link below is interesting too, but in Polish. Site was set by bloke which lives in Pustkow, little village near Blizna.
I can assume that he get his information from relatives which witnessed visit of British scientists when soviets took the area in 1944.
According to him soviets took Blizna 1 of August 1944.
British mission headed by Sanders, (no first name mentioned), arrived at
3-rd of September 44 and stayed until 22 of September.
They packed many wooden cages with rocket parts.
After their departure soviets combed the whole area and took more parts.
I don’t know where info come from, but he stated that during transport soviets replaced parts with metal scrap.
It would be interesting to find if soviets allowed the same British team to Peneemunde.
http://republika.pl/pustkow/blizna.html
Cheers,
Lancer44