Oh, here is my theory: Hall traced an early version of the schematic. My reason for guessing this is the wiper motor shown--in the Hall schematic, shown as a 4 wire motor but in the Italian schematic (dated 11-1-68) and as installed in 8ma1046, definitely a 5 wire motor.... Everything you want to know about Lucas wiper motors are here, http://www.mgb-stuff.org.uk/wiper3.htm#none
somewhere around ~1967 Lucas transitioned from 4 to 5 wires and 2 speed motors. The 4 wire motors took +12v to the motor and switched ground, the 5 wire motors mux +12v in the switch....Originally I followed the Miura wiring, http://www.huskyclub.com/tavwiper.html , but the Italian schematic is consistent with the +12v used for parking...Lee