Peg Leg

I have often wondered how the shots of Douglas Bader walking with the peg leg and crutches were made. Did they have to bring in a double who was an actual amputee? Or was it some sort of trick photography, with a special prosthetic shoe made to look like a peg leg? All of the shots that show the peg are of his back, or of just the peg leg and crutches. So who was the double who played Bader with the single peg leg?