I think it is admirable to campaign for this but I fear there is no political will to make a difference. Primary school places are a concern to a small number of people for a limited period, and busy parents aren't even particularly likely to vote for local councillors, especially if they are end up moving away to live closer to their child's allocated school. There is far more mileage in campaigning for green issues or protecting historical buildings. As an example, the crisis could easily be solved by using land at Vinery Road allotments, which is immediately next door to St Philips, but allotments have broader appeal than school places, and no politician would dare suggest something so controversial.
In 2009, just a few years after knocking down and selling off Romsey Juniors and Sedley Infants, the County Council woke up to the impending crisis, and a review was underway(!) They decided to expand St Matthews and Abbey Meadows to 90 intake and to build the new Queen Emma school at Netherhall. Morley and St Philips were ruled out because they are on small sites, although I suspect there's more to the St Philips decision than that, as the school's footprint is a similar to size to St Matthews, which takes double the number of children each year. Ridgefield was too difficult/expensive because it's in the flight path of the airport so couldn't be built too high or using cranes.
So it was six years ago that a tacit decision was taken to have mega-sized primary schools instead of community schools that local children could walk to. This is clear from Queen Emma's giant catchment area, which encompasses the whole of the Queen Edith, Morley and Ridgefield catchments. Had they expanded the Abbey Meadows catchment southwards at the same time then Romsey families might have got used to the idea of sending their children there; it's a similar distance to Queen Emma. In fact, Romsey streets north of Fairfax Road are about to be kicked out of the Romsey electoral ward and put into Abbey anyway, so perhaps that's where things are heading.
The admission arrangements for 2016 have already been 'determined' in a consultation which ended in February this year. The only wild card is a spare classroom at Ridgefield. In 2009 there were two reception classes, and these children have been gradually working their way up the school. They are about to move up to Year 6, and then in September 2016 there will be a unused room for which no plans have yet been made. The Directory of Schools will say there are 30 places, but in that situation they would have to lose staff and suffer a cut to their budget. Alternatively, if things get really bad, an extra class could be put on at the last minute and the County Council and some local politicians could turn the crisis into a heroic good news story!