I have been unable to find (in the 747-400 engineering manuals) any data paths from the Flap Control Units to the Flight Control Units which contain leading edge flap position information.... only inboard trailing edge flap position. Ref wiring schematic 27-51-04 Sh 2
Is this what you are looking for?
https://drive.google.com/file/d/0B-W...ew?usp=sharing