It is no problem to use the LHD harness . The loom to the head lights and tail lights work just fine as it is easy to "rotate" them to suit. All you have to do is extend the horn wire and the wire to the generator . I make sure I have a good watertight connection and use small cable ties to secure the extended wires to the left hand head lamp loom which runs across under the radiator . If your clips are intact to hold the loom on the rad bottom they work just fine.
John in light rain sunny tommorrow Suffolk County England .