RELAIS embroidered duster sweater long cardigan M L

Long duster cardigan from Relais, so beautiful! Heathered black-gray, with crewelwork style embroidery. Button front. Tagged as a L, and could probably fit a L if worn open, but if you plan to wear this buttoned up it will fit more like a M. The mannequin it's shown on here is a size 4. When buttoned, this measures 21" PTP. 48" long. Ordinarily that does fit a L, but my client said once she layered it over other things, and tried to close it, she felt like it would have been better for a M? So this only got worn a couple of times and still looks almost new!