Just ordered and sent back 3 dresses from White Stuff because there was insufficient fabric in the bust to cover my bra. No, I am not wearing Madonna's virgin tour bra c1980s, nor am I particularly huge of norkage. I am an average size 14 with size 34DD bust. I bought the dresses in a couple of sizes (14 & 16) and all of them were woefully inadequate in this area. The underbust (empire-line) seam sat right on top of my nipple line instead of nicely below the boobs.
If any one from WS is reading this; please understand that you can't just size up from the basic size 8 pattern by making a garment wider: you need to account for changing proportions and curves. The average cup size increases as the dress size increases.
WS garments seem to be cut for the carrot shape! They look great on the hanger but rubbish on a real body like mine.
Other main offenders IMO are Gap and Next.
Right, glad that's off my chest now.