Recently converted mine using a universal H4 harness that plugs into the socket that fits on the back of the headlight bulb. The downside that I may need to overcome is the single point of failure if the fuse blows but I would still have sidelights which are part of the headlight unit and on a separate circuit. However, my reckoning is that if the fuse blows on a normal headlight circuit it would cut the dip beam and if that happened I wouldn't drive round with main beam on instead. I would use sidelights which is what I have. Cost me £13, I didn't have to cut anything and it looks pretty tidy. Mine uses the LH headlight as relay switch feed and the live runs under the inside of the wing in the engine bay to my battery which is on the LH side being a RHD car. Simples!