Funny thing, sometimes I'm able to answer questions here without recourse to a search engine
The answer is : Character : David Maltby, Actor : George Baker.
The answer is available in John Ramsden,
'The Dam Busters' ( IB Tauris 2003 ) as well as 'After The Battle' magazine. And maybe could be answered by anyone who has paid more than passing attention to both film and actuality.
Your question.