I only ever got one helmet in the post and it was packaged just as you describe.
However mine was a freebie for subscribing to TWO magazine so i really wasnt bother about how a FREE lid was packaged.
TBH, i wouldnt worry too much about it and i sure as hell would not pay to return it for a 10mm scratch, unless the scratch was all the way to the base of the lid and therefor stood out a lot.
Just mho