Good job I'm not a betting man..... Those photo's have completely thrown a spanner into the works as they are clearly not charcoal in those images! Back to the drawing board and I can start to see your builder's problem now, getting a match isn't easy!
Maybe worth having a look at reclaim yards, they may have some weathered blocks available that would give a better match.
Maybe worth having a look at reclaim yards, they may have some weathered blocks available that would give a better match.