You would think this relatively easy???
Nooooooo ........ it's impossible
I'm a 30FF in bravissimo
A 32E in boux Avenue
I'm having nipple surgery in 2 weeks and need a soft, non wired, do up at the back bra
I went to M&S, the woman measured my chest!!!!! Not my breasts or under, my actual frigging chest - then declared me a 34DD
Surprise surprise they all felt awful, riding up the back, too loose, masses of cup room and vile fabric
Bravissimo could only offer a sports bra in a G cup. A sports bra is no good as too tight & fitted.
Normal shops only do 30-32 in an A-C cup because slim women don't have boobs
Only women who are a 34-38 can have boobs D-G cup apparently 
Tried Debenhams and that was a similar story to M&S
Please help