Multicultural kids

I am reading so many interesting articles at the moment about culture and identity. How, for example, do kids with parents of different originis define themselves and how does society define them?

My kids have always felt more Icelandic than British, both in Iceland and abroad - except Sandra who felt she was Indonesian when we lived in Jakarta...) but they still feel some connection with England. Now that their grandparents have moved to New Zealand the link has somewhat been broken and they wonder if their roots moved with their grandparents or not? At least they have strong links with New Zealand with their grandparents living there and their only cousing being a New Zealander!