I have both a Sept and a June baby at school (well not babies anymore but YKWIM). My Sept boy (M) needed an extra year but my June boy (A) didn't and I think he would have coped just fine if he started school at 4.5.

I LOL at trend. It's not a trend at all. More like the parents being more in tune with the needs of the child and not sending them to school whether they are ready or not.