The Wellington certainly did appear in The Dam Busters (flown by Patrick Barr playing the part of Mutt Summers), although of course the Lancaster had the starring role.
Barnes Wallis is seen waiting to see someone at the Air Ministry to ask for the use of a Wellington for trials. "Would it help if I told you I designed it?" is the line immediately before the Wellington takes off.
Smart ar$es, don't be so quick to criticise!