Actually, it is not as hard as many people think. It depends on how old the Defender is. On most of the early ones, the RHD and LHD bulkheads are identical. There is a small amount of cutting to be done, but all of the mounting points for the pedal box, steering assembly and brake servo are already there. There are already holes in the bulkhead for the wiring loom and speedo drive etc, on the LHS of the bulkhead, so all you need do is fit a LHD dash, and move the bits across. You will also need the LHD steering links. These should just bolt on as the axles & hubs have fittings for both LHD and RHD setups.