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The 500 switchgear wires go through the bars. Take some pics of the switchgear and the bars themselves. If at all possible see if you can find original 500/550F bars, not 550K3 bars. I'll measure the top yoke and bars serrations on mine and see what they are.
The serrations are 100mm wide from middle to middle, the holes in the top yoke are the same size, so the serrations should match the bolt holes exactly. Check both the bars and the yokes to see which one is wrong.
If DS are selling CB550F bars with the holes make sure they are UK bars not USA bars before ordering.