What a sad story about your f-i-l DaisyNonna, a very brave man.
I used to be based near the Mohne Dam and on quiet nights when on patrol would take a run down to the dam and walk to the middle of it. One could imagine the Lancaster's as they made their passes, marvelling at the bravery to hold their flight path as withering AA fire was concentrated at them.
And yes, the film evokes emotion for many. Even Barnes Wallis himelf was left devastated by the amount of Allied airmen who were lost during the raids on the 3 dams.