The White Company Indigo Blue Linen Button Side Dress.
They say:

What We Love

In indigo linen, giving it the relaxed look and feel of your favourite denim, this dress has a simple, straight fit. The drop-seam waist is cleverly inserted with broad pockets to the front – we think it’s super-flattering on straighter silhouettes. Buttons to the sides allow you to tweak the shape. Just add sunshine.

100% linen
Machine wash
Label size UK14.
Measurements of the garment: Armpit to armpit - 23'', Length (shoulder to hem) - 37 1/2''.
This dress is in excellent condition. From a smoke and pet free home.
Thank you for looking!