My Dad made a big thing when we moved out of London ( Zone 6 type expensive green Commuter belt area). We moved into North Hampshire. He basically was saying that outside the magical barrier of the M25 that the level of education is a lot lower. My Dc are just at the start of their school journeys and I have nothing to compare to. But his thoughts were that if my DC was top of their class in Hampshire that would be lower than in London. I'm guessing this depends on area of London? Also our estate agent said we shouldn't move out as we would struggle to get back in.