i bought 2 macoms, normal back size and one up and neither fitted me in the cup after my op and didn’t a week on (got rid of them now so don’t know if they would fit now) I would say buy a macom as most have no problems maybe get one of ebay of here if you don’t wanna waste the money on one.
i was predicted a 32e from a 32b of my surgeon with 525overs. I bought a 32E asda which deffo didn’t fit. 2 macoms, didn’t fit. luckily had bought m&s 34ff zip up front, that fitted straight after op… I’ve since been measured 34ff in a freya bra and a 34g in high impact m&s 2 pack sport bras (i’m 3 week post op)…it varies store to store, so deffo keep your receipts if you are buying a few, to take them back if they are not needed. I’d say get a macom and a couple of others just to be safe…. but i know some girls just get the macom xx