Finding housing as a young couple with a child (London)

Hello! I'd just like to ask, does anybody here have advice to give to a young family of three trying to find a place to rent in London (hopefully, in Ilford)? My friend has been fretting terribly over how they'll pull this off, and I can see where he's coming from - it's difficult enough finding good housing on your own, much less with a partner and child. They've been looking through sites like zoopla and rightmove but so far affordable family friendly rentals are few and far between, and so I was wondering if there might be other sites/resources that would be useful to them?