I do not know how many Mosquito used for the filming. But at least three of them are destroyed. As you can see on the scene:
1) one that run into fuel bowser
2) one that collapses undercarriges and came to rest on it belly, and
3) one that force landed and burned on the last scene.
Ohter aircraft includes a T Mk3, RR299 which was crashed in '90s.
In one respect I personally do not like to watch "633 Squadron" movie because so many flyable Mosquito were destroyed before you, although the movie itself was an enjoyeable and exciting one. I admit the movie was one of the best aviation picture ever filmed.
As far as I understood a person in New Zealand has completed the fuselage shell of the Mosquito. Wings are of rather conventional construction, using laminated spar and thick plywood. In my opinion, finding plywood thick and large enough to cover its upper skin (in double construction) can be a problem. But I am expecting it to take to the air again some day.