Thanks for everyone's replies, lots of food for thought.
I was reaching for the bottle, so thanks @RosieSpark and @Robostripes for providing a glimmer of hope.
We both work, (my partner and I) so the idea is drop off DC on the morning commute to work, pick up on the way home, school has wraparound care, clubs, etc.
Train delays are a worry, long day for DC is a worry.
We drove to the school in rush hour as a test run and it took a good hour, with morning rush hour traffic, less so in the late afternoon.
So getting DC to school by car is a possibility, not something I'd like to do, especially for the environment, although in theory could park up near school, drop off DC, go to work.
God forbid but DC sick at school, would cab it home, same as delay or train strike, again anal as we are, we checked prices and as one off it's not too painful, every day less so!
We'd be less worried about playdates and parties as I'm hoping they'd be like pre-school and mostly at weekends, and at the weekends it's about half hour drive to school from our house, so anything local to the school won't be too painful by car. I know we'd probably be the pariah's for people coming to ours.
As much as Im grateful for parents opinion's we do know its a shit idea, we know it's far from ideal, but particular set of circumstances means literally move into a shoebox to live locally (its mega expensive to live anywhere close to the school) , or give up on the school and go local state, where all the schools in our catchment are 'Requires Improvement' or just 'Good'. True with lots of support, a child can even thrive in a primary school that 'Requires Improvement'.
We wouldn't opt for private schools a little closer ( there are some) as they seem just OK and my partner isn't prepared to pay for anywhere but the 'top rated' or bust, I agree.