Well it seems only the first prototype(s) had the nose-only air intake. On later prototypes they combined it with side intakes or even replaced the front intake all together with side-intakes. Difficult to see on the limited photo material available. Using side-intakes only, would have improved cockpit comfort considerably. Don't understand why they started with the nose intake in the first place....
Won't give the answer though; found it by CSI techniques, not aviation knowledge, so won't take the fun out of it...