It's really weird. Working in fashion retail, the people who work in the garment tech departments do know exactly what they're talking about. Whole collections and moodboards are built off trends with names ("we need more midis this year! Midis are in!") so while I can see one or two falling through the cracks, I don't understand how M&S manage to get it so consistently wrong.
I wonder if we should put together an email from all of us and send it to them.
I'm not sure I would call this "round neck", especially as they have referenced roll neck, turtle neck and funnel neck on the same page, and list all their actual round necks on tees for example as correct: