I wonder if Margaret can find this photo useful to give us a size estimate?
Looks like she’s roughly a 29” back, but more like 30”.
I previously said: “Given her height and frame, I'd suspect she's in the 30K, 30KK or 30L category. Possibly 32K, as she looks broad.”
I’d be definitely thinking 30L, as her bras tend to look a bit tight on her and her centre gore pushes out slightly - so she’s clearly struggling to get bras in her size. So, a 30L would be about right.