Best expat living areas in Hanoi?

Hi, we are in HCMC and may have to move to Hanoi very soon. We have 2 babies aged 2 years and 8 months and are Australian/English bin HCMC there are specific districts all the expats live and that have all the popular expat places to go and stuff for kids.. Is it the same in Hanoi? Which are best areas? Are there a lot of expats? And families with young children? Any help would be great!! Thanks