Wild guesses, de wrong answers...and Tony Williams mentioned it yesterday
Smith invented the 'de Wilde' explosive .303 round used in limited numbers, but with great effect by Fighter Command's better shots such as Stanford Tuck.
To confuse the issue, he did not invent the
real 'de Wilde' round which came from Switzerland but the British round was allegedly named thus to confuse the Germans as the real dW was difficult and time-consuming to produce - Major Smith's bullet was quicker to make.
Over to you, KM - the effort of giving all the clues has given me a headache...