Just buy the MaCom hun – https://www.macom-medical.com/products-40-breast_augmentation_surgical_bra.html Type “mybreast” in the promotion code box for 15% off.
The cups are expandable so it fits nice and tight no matter how swollen you are, and afterwards. And it does up at the front. You only need one bra, and in your normal size.
The M&S and asda bras irritated my very sensitive breasts as they have seams on the inside. They also do up at the back which is awkward.