I'm GUESSING here, but here goes... (Don't blame me if you let all the smoke out of the system!)
E = "Earth" = Chassis ground
D = "Dynamo" = "ARM" in US terms connects to "D" on generator.
WL = "Warning light"
F = "FIELD" Connects to "F" on generator
B+ = "BATTERY" in US terms... connects to ammeter or direct to battery, if ammeter is not used.
Take a look at this VOLKS wiring diagram, IGNORING the components other than the charging system.... the Bosch or Lucas connections should be about the same.