The band is pretty much the same in both bras. The 28DD bra has wider cups but they are both about the same depth.
Discovering Katherine Hamilton: Sophia (30GG & UK12)
26 Bands and HH Cups? Reviewing Katherine Hamilton's Sophia Bra
26 Bands and HH Cups? Reviewing Katherine Hamilton's Sophia Bra
Fuller Bust Bras Size 26-38 D-HH - Katherine Hamilton
Bra Fitting Guide - Katherine Hamilton
Comparing a 26F Katherine Hamilton Sophia Bra with a 28DD Cleo Meg Balconnet (6751)
Fuller Bust Bras Size 26-38 D-HH - Katherine Hamilton
Sophia Balconette Ivory/White Lace Bra with Silk Quarter Cups - Katherine Hamilton
26 Bands and HH Cups? Reviewing Katherine Hamilton's Sophia Bra
26 Bands and HH Cups? Reviewing Katherine Hamilton's Sophia Bra
26 Bands and HH Cups? Reviewing Katherine Hamilton's Sophia Bra
Fuller Bust Bras Size 26-38 D-HH - Katherine Hamilton
Discovering Katherine Hamilton: Sophia (30GG & UK12)