It was intentional as I was attempting to make additive changes where I could.  If someone had some code that asked whether `long_name` was 'z' (as it was before this PR), then it would not fail as a result of my changes.

I'll remove it as I guess if we are interpreting the field header correctly now, we shouldn't keep redundant information as it suggests that its been 'interpreted' when it hasn't been.  Cheers @rhattersley