In response to the OP, my village school is massively oversubscribed, due to 2,000 new houses buing built on the outskirts of the village. The nearest school to these houses is actually in the next village, however for parents that work this would mean driving to the school then driving back on themselves to get to work. (We live on a peninsula, there is only one road off)
This has resulted in many children who live closer to the school being allocated a place at a school 3 miles in the other direction, which is fine if you are dropping them before work as it is on your way, and of course if you drive. Plenty of people don't, and are struggling to get their children to school along a lane with no footpaths. Often walking past the village school on their way.
This is causing masive resentment towards the people who live on the new estate, particularly from those who have grown up in the village, and now can't get their children into the local school. It is not these peoples fault of course, but the infrastructure here is creaking under the weight of the new houses. More are due to be built, and this lack of foresight by the LA was, I believe, a big part of the reason that we recently ended up with a UKIP MP.
WRT the summer born issue, DD will be 4.2 when she starts school in September, and will probably be ok. Her best friend will also be 4.2, has a speech delay, and has just been told that she won't get into the village school with all her friends, which is a massive deal for her.
I see no point in delaying dd, she will only have to go into year 1 next year (because the school is so oversubscribed) which means the other children will all already have their friendship groups etc. I think it will be harder for her in the long run so have decided to just suck it up. She is fairly confident, and I do believe she will be fine, but plenty of 4 year old wouldn't - her best friend being a case in point.
I envy the Scots their system tbh. The biggest problem surely is the massive gap in standards between some schools - if it were an equal palying field I am sure most parents would just choose the school nearest to their house.