The following paragraphs are from research I did sometime ago, please correct/add to them.
The legend of a false map given to the Axis is true but to what extent it was really followed at unit levels is not clear. It is likely that the ground beyond Samaket Gaballa where the Crusader Squadrons of the 3rd and 4th CLY were to deliberately retreat to whilst keeping the enemy under fire, had been drawn on the map as soft to encourage a turn to the north sooner rather than later so that they came to face the grants at Alam el Halfa instead of 131 and 133 infantry Brigades or worse out flank the ridge to reach the coast road. Some soft areas had been shown as hard but only areas where it was known the Germans had not operated could be wrongly described with confidence.
Brigadier Freddie de Guingand, Chief of Staff, Eighth Army
“We had up till that time produced no special maps depicting the “going” of the ground; and now our Intelligence boys concocted a false map, showing splendid hard sand in the Alam el Halfa area. This map judiciously aged by the application of tea stains, was planted in a British scout car which was allowed to be blown up on a minefield. The Germans captured the map and allowed themselves to be thoroughly deceived by it.”
Captain Peter Vaux was an intelligence officer within 7th Armoured Division HQ and assisted with this deception sometime around the 20th August. The map was produced from intelligence gained from reconnaissance troops marking their maps with coloured borders for areas of “going”: Red for firm and clear for fast movement 10mph or more; Yellow for 5 – 10mph; Green to advise units to check the area before driving over it and Blue for impassable. Captain Vaux made the false map, stained it with tea to age it and then folded and refolded it to make it look believably used; then from his O.P on El Himeimat, watched an intelligence section drive out in a scout car until they drew fire and retreat on foot leaving the map and other kit to be found. Vaux later watched a German patrol reach the car and take the map.(148)
Under the post-war pseudonym of Paul Carell, Allgemaine SS Obersturmbannführer Karl Schmidt who had been a Pressechef during the war with responsibilities for German news and propaganda releases, refers to Vaux’s map indirectly in his 1958 book Die Würstenfüchse. Schmidt states that he was assisted in writing his book by General Fritz Bayerlein who produced a German map of the operation which showed clearly in colour and text information on the state of the terrain beyond the minefields. The information had been gleaned from a map taken from a blood-stained map case removed from a scout car blown up in a minefield. The map had been examined and assessed as real and a reliable source of the information on which a timetable of movements could be produced. Schmidt describes that where the Allies were expected to be weak they found strong positions; where tracks were shown they found “heavy sand dunes” and where sand dunes were marked they found strongholds which delayed progress.