Outer sill replacement

[nthomas1]

I'm facing another tricky decision as I progress with my Series 2 Coupe rebuild. Should I replace the outer sills?  The existing ones are in good condition as far as I can see, but a previous owner has riveted 'L' section strips over the flange under the edge of the outer sills. These make inspection difficult, and don't look that tidy.  As I'm having a full respray of the car, I'm tempted to remove these strips and replace the outer sills.

On the negative side, I'm worried about the amount of work involved in replacing them, especially as the ends of the outer sills seem to tuck inside the wings. Question: does replacing the outer sills involve cutting out a lower section of the front and rear wings corresponding to the projections on either end of the new sills? Also, how should the wings then be made good..... do fill-in panels have to be welded in place?  I can find pictures of people replacing outer sills at the same time as replacing the wings - but none of somebody replacing only the sills.

One more question: Looking at pictures of new outer sills, it appears that the lower flange is not full length. Can anybody tell me what makes up the end pieces of the flange under the sill that run to the wheel arches? Are they flanges on the bottom of the wing, or possibly on the rear floor panels?

Any advice, as always, would be greatly appreciated.