My best fitting bra is a 36 e non padded from debhnams it's really comfy fit and covers cup fully. I got more In this size from M an S pay a far amount and they feel tiny can't return them. I measured myself and my band is 36.5 and my breast when I bend over I think this is how you do it is 45 so what size sould I be
Your measurements suggest a starting point of a 36G. Can you pop your 36E on and try scooping vigorously.
-put your bra on by leaning forward and dropping your breast tissue in to the cups -fasten bra -stand side on to a mirror, put your left hand inside your right cup, reach round under your armpit and pull forward any soft tissue that's lurking there -repeat on the other side
I suspect either the 36E is a mis-label, or after scooping it will be far too small and it's not been encasing all of your breast tissue