It wasn't just the boost it gave morale in this country it also was very demoralising for the Germans who had bought into the invincibility of the Reich until then. It took 6 months to get the Moehne rebuilt, 6 months interruption to the war production in the Ruhr shouldn't be underestimated.
I recall when Michael Redgrave died and the film was shown on TV, out daughter, about 6, told her Grandma that 'those naughty men have broken our dam', we didn't live far from it and used to sail on the lake, my Mother went mad and she got a lecture on WW2. We were terible parents for letting her think that apparently!