Your friends would rather have 'diversity' than the comparative lack of crime/violence and exposure to drugs that Sussex vs Inner City London life would present to their children - I say again perverse!
You are not going to get a roasting from me, what you say seems very sensible. Indeed anyone that wanted their children to grow up in Inner City London (and no I don't mean Chelsea and Westminster) when they had the alternative of (most of) the lovely County of Sussex would be rather perverse.