Correct LH skin 8 trailing-edge fold error

The LH skin 8 had a positional error in the trailing edge fold, enough to cause severe curling when clecoed in place. I elected to adjust this fold by the required 1mm or so. A steel anvil was machined and the fold "rolled" into the correct position with a nylon hammer. Some evidence of cracking appeared at the very ends of the new fold, these were stopped out by notching with a needle file.

Note that these skins are custom replacements supplied by Sling with a number of holes missing. The original skins, which are otherwise good, had considerable hole mismatch with rib 11 and skins 5 and 2. If I screwed this up (and I may have, with the cracks) I can possibly revert to these or more likely, copy and make new skins out of sheet.