That is what I said. Sophie with Peg & Lu took charge of the motherless children. However after her remarriage, she was taken out of the equation. Both Peg & Lu took an interest in the children and their imput should not be downplayed.
Actually, the Mountbattens were closer in blood to the House of Hesse And By Rhine than the Hesse-Kassel Line. VMH was the eldest surviving sister of Grand Duke Ernst and aunt of both Don & Lu. So in terms of bloodlines, the House of Milford Haven had a better claim I think.