Yes, but I was talking about close as in good friends. Anne and Charles did not grow up with the Kent children as they were much older. Andrew and Edward did, however, grow up with them and with Sarah and David (and James and Marina, Alexandra's children). They all spent Christmas and summer holidays together and they mostly ran in the same circles as teens and young adults. They all married within a few years of each other and their children are also pretty close in age. Charles and Anne's children are much older than the Kent grands, too.

I think Anne was included as she was a junior bridesmaid at the Duke and Duchess's wedding. Edward was out of the country, Louise was at uni, and it may have been decided it was better for James to stay in school. Lady Sarah's sons grew up with Helen and George's children and the Gloucesters, along with Freddie and Ella, grew up with Nicholas and so that may have been why they were invited.

The Duchess's nieces and nephews were all there, too (I think), along with their children. She was close to her brothers and their families.