Pillow-fights are being merged. From this September, the girls of St Mary's Wantage and the girls of Heathfield, Ascot, will be playing and studying together on the Heathfield site. The merger just announced between the two 200-pupil boarding schools, to form Heathfield St Mary's, makes perfect sense. Both are posh, Christian and quite academic. St Mary's, frustrated at being unable to expand on its present site in Oxfordshire, has failed to raise enough money from selling it to buy a larger one. Heathfield, meanwhile, has space aplenty but lacked the cash to expand. Together, they can make - er - a performing arts centre. The name of the PR firm advising on the merger is Financial Dynamics. But will the exuberant girls from St Mary's overwhelm the delicate flowers of Heathfield? The Good Schools Guide says the latter need stability and cherishing.