I’m rather late picking up this pub review from the Daily Telegraph, but if you are ever in the Howden area, this sounds like a good place to get your Barnes Wallis quota up to date. Plus they do portions huge enough to defeat even the hungriest of Telegraph reviewer’s companions. According to its own (idiosyncratically designed) website the Barnes Wallis Inn has extensive Barnes Wallis and Dambuster memorabilia on its walls. It would be interesting to find out what this comprises, so if any locals read this, please let me know.
Dambusters Blog 
Also worth a pilgrimage are Lincoln’s Olde Crown, with pics of its former patron Gibson, and the Windsor Castle on London’s Crawford St., which displays his flight log.