Just been measured in M&S and they said 40A and they do seem to fit. I've measured myself at home and I'm a 37 around the ribs and 41 chest which would be a 38D?
That's what I'm currently wearing but there's too much room in the cup. Now my boobs have shrunk and sagged since my baby is no longer a little baby I am really struggling to find a bra that fits.
I'm broad and bigger on the top. I'm a size 14 bottom 16 top.
AIBU - just buy the 40A
YANBU - go somewhere else!