The three leafy acorns (from the great English oak representing strength) represent each of Mike & Carole's three children. Apparently, an idea suggested by Kate, but who knows. The gold chevron in the center of the design represents Carole (nee Goldsmith) the matriarch of the family. The thin white cheveronels, above and below the gold cheveron, symbolize peaks and mountains apparently reflecting the family's love of the Lake District and skiing. The half-red and half-blue background is to distinguish it from a similar 16th century coat of arms.
The only item missing is a family motto, which I don't think is a requirement, but it would have been nice.
It's simple and lovely. Well done!