why is david lloyd george not held in the same revere as Churchill?Watch
"Lions led by donkeys" is a phrase used to describe the British infantry of the First World War and to blame the generals who led them. The general impression was that the brave soldiers (lions) were sent to their deaths by incompetent and indifferent leaders (donkeys). Maybe read some War poetry form that period? Dulce et Decorum Est by Wilfrid Owen is a good start.
World War II was a much greater struggle than World War I from our perspective. In World War I we had many allies in Europe such as France, Italy and Russia, whereas in World War II following the Fall of France Britain and its empire were on their own against the Nazis until America and the USSR joined the war. The Second World War was also much closer to home with things like the Blitz whereas in World War I very little fighting actually took place in Britain (Lloyd-George didn't have to make important speeches about fighting on the beaches, landing grounds etc. because it never reached that point). Since the struggle in the Second World War was greater I would say that this is part of the reason why Churchill is more celebrated. Also WW2 is more recent so we remember more about the people in WW2 than in WW1.