"Well at a guess the tabs don't belong to me as the affected lines aren't in this diff and nor are they edited/added by me".  I  have discussed this issue w.r.t. reviews before.  I don't care where the code from - I am reviewing it as it is now, and I happened to notice this particular issue.

I agree that whitespace changes should not be mixed in with other commits (if that's what you means by messy diffs) as it makes it hard to see where logic has changed.

Anyway, I've fixed it.