Trying to model the maths: stay until 13+ at a slightly stronger range of schools, vs leave at 11+ now and start senior sooner.
DS is at a prep that goes to 13. The 13+ schools available are arguably broader and stronger than the 11+ ones we'd realistically aim for. But the 11+ window is now.
How did you frame the decision? In hindsight, what mattered more than you expected?