I am not sure about it.
Some of the DC who seem "not ready" half way through reception make rapid progress later on and overtake peers who seemed ready earlier. Development isn't linear or even - its often nothing, nothing, Click!
You'd end up with DC being held back because reading hasn't clicked, suddenly leaping ahead in october of their second go at reception.
I see why they are considering it though. Children from poorer homes regularly start school absolutely miles behind better off kids, developmentally. Poorer speech, parents who've never shown them a book, who don't know how to play simple games & haven't had access to craft materials. better off peers have ridden bikes or horses, have play equipment in large gardens at home and are often physically more capable too. This is why its much more common for poorer kids to not be assessed as a "good" level of development per EYFS.
Offering a second go at reception would help to "close the gap" by giving these children who are behind a full extra year of free education to catch up, meaning they are then older/more capable when:
- taking sats
- taking 11+ tests
- sitting gcses and a-levels
The difference would be huge. If the social stigma could be dealt with, it could alter their self perception too, instead of feeling behind, they would be more likely to leave reception confident and feeling like they are "good at maths" etc.
I'd prefer it to be done as a deferred start for children deemed "not ready for reception" with a year in an alternative provision like a good quality low ratio nursery, however. No one likes having to repeat a year.