The Mosquitos 'skip bombing' are using 'Highball' a smaller, more original design of bouncing bomb with the spherical case.
Unlike what's implied in the illiterately captioned film, the Mosquito work was not 'training' for the 617 Sqn Dam busters raid.
The unit was 618 Sqn - and they did not get deployed because of a/ 'we' didn't want the enemy to discover a secret weapon and use it against us (the 'public' story, bunk) b/ conventional bombers using conventional bombs did nearly as well (a factor) or c/ issues with holding back British or Commonwealth units in favour of US ones in the Pacific for reasons of supply chain or glory/prestige (apparently documented) d/ suitable targets never eventuated (probably a factor).
http://en.wikipedia.org/wiki/No._618_Squadron_RAFAn interesting case of a mostly-forgotten secret weapon. Some 618 Sqn four-blade engines survive in Australia.
And the fatal land accident in the film is of a twin - either an Douglas Boston / A-20 or an A-26, and again not Dam busters training. I recall the story vaguely, but don't have the details.
HTH,