Just wondering if you might be able to shed any light on where I'm going wrong.
Used to be on 36C back in the day. Re-measured myself and I came up at 32G or GG (don't have a tape measure to hand, unfortunately).
I'm in NZ and it's impossible to get small back/large cup bras - in fact, it's basically even impossible to get bras in a 32 back or smaller, even in A or AA cup! 
So, I had to order online from the UK.
The G cup just didn't ring true. I have very modest, hollow boobs. Sure, when I lean forward to measure, they swing down like golf balls in socks, but there was just no way they would ever fill a G cup.
I ordered a 32F, and even with all the scooping in the world, the cups were not full.
Tried an E, same thing. So then tried a D and that seemed much better. However, I have back fat?! Even though I scoop, and scoop, and scoop again.
I know this suggests the back width is probably too loose, but when I measure myself around the back, under my boobs, it is 32. I can probably get it to 31 if I breathe right in, and pull it super tight.
I am a size 10, BMI 21, but tall with fairly broad shoulders. I know 32 is pretty much on the biggest end of the scale, under the new, improved measuring system, and someone who is a size 10 wouldn't normally be 32.
Any ideas? Should I go down to a 30? It's such a pain having to rely on mail order. I am in London at the mo, but with kids, so not really able to go bra shopping. However any recs for good stockists in central London would be much appreciated.