Sorry, phone skipped the page where OP had found her true size! Anyway, this is my ultimate favourite bra, I refuse to wear wired. Looks like stocks have run out from this supplier though...
My bone of contention is that it is virtually impossible to buy a non-wired bra in Primark. Occasionally they have some cotton ones, but only ever in white never black.
OK interventionists, my measurements are 36 underbust, 43 when flopped forward! I can't fill any cup size bigger than a B, I'm certain (although it's been about 6 years since I tried anything different during my fruitless summer search for a black cotton bra!)
Oh you are so not a B cup! Try 36F as a starting point! I'd try 36F & FF and possibly a 34FF & G. Depends on whether you are somewhat squishy of torso (like me!) or have a bony-er rib cage. If squishy you might find the 34's better.
Lordy!! Thanks Sparkling - I am chubby of front and back squishy so I will take your advice. I can hold up my head with pride in Primark now However I'm certain I don't have 4 booby-ness and my gore does lie flat (well, it's where I keep my cleavage tbh). But even at my advanced age and having BF 1 DC I still pass the pencil test - cannot grip anything under a boob at all.
I'm certain I will be posting a pic of all the empty space in an F or FF. But as I must have been an adherent of the "Add 4 or 5 inches before you begin" school of bra fitting I may have a lot to learn!