This, particularly the bomb disposal, rang a faint bell remembering Ronald Pickup playing such a role on TV many years ago - god knows how some of these things stick in the memory..
IMDB gives the following summary for "The Dragon's Opponent" as confirmation
4-part miniseries (1973) dramatising the true-life adventures of Charles "Mad Jack" Howard, 20th Earl of Suffolk, whose daring wartime exploits included rescuing dozens of refugee European nuclear scientists, a large supply of heavy water and millions of pounds in diamonds just before the Germans captured Paris, and then became a self-taught bomb disposal expert who successfully defused dozens of large German bombs during the London Blitz.