Maybe you guys can help me out here with a movie I have been trying to find. I rented it a few years back from a small video store that is now closed. It was set sometime after the Battle of Britain...and depicted London under attack from Hitler's Vengeance Weapons. In the beginning, you'd hear and see the V-1s buzzing and exploding in the city....and later in the movie-- they did a great job of showing the V-2s in action-- you'd see this HUGE explosion, and then shortly after hear the rocket engine noise.

I have no idea of the cast or anything like that-- it reminds me a lot of the Battle of Britain film, but is later in the war. I know it isn't "Operation Crossbow" as someone on another forum suggested as that was sort of a strange George Peppard flick

Could it be Mosquito Squadron? With David McCallum from the Man from UNCLE?
That was about a squadron that had to go attack a rocket site that was being protected by using POWs located nearby. They go on a daring raid to destroy both the research bunker and save the POWs.

It had stock footage from a number of other films, 633Squadron and 'Operation Crossbow'.

I remember a movie that the sabotage group went into an underground complex and had to set up bombs and such to destroy it. Had buzz bombs and V-2's popping LOndon, can't remember name or actors though