I was thinking that the fired brass looked about average for a SMLE. They seem to run longer in the shoulder area than most of my No.4s. No.3s have yet another average look to 'em after firing. The scored areas do seem to indicate some crusties in the chamber walls, though, but not horrible.
But if the rifle's not doing right, then there's only a few usual culprits. Either chamber or extractor assembly related.