Vintage Style Retro Heyday Olivia Blouse Maroon UK Size 20 about US 16 or 18

Unfortunately, the tag was removed from this Heyday brand Olivia style blouse. I believe it is size 18 or 20. Although fabric they currently used is a rayon/viscose, this blouse feels more like a sturdy cotton/poly mix. Adorable flower buttons detail. In excellent condition with no rips, tears, stains, etc...just a missing inside label. See photos for measurements. Please message with any questions.