By 1859 the Board began to consider a permanent site, eventually settling upon a plot in Purley. The foundation stone of the new school was laid by Edward, Prince of Wales who also returned in 1866 to officially open the school.

The demand for further places from war orphans led to an offer to purchase the Ballards Estate in Addington. New buildings were added, designed by Sir Aston Webb, the leading British architect of the day and well known for the new front of Buckingham Palace, Admiralty Arch and the Victoria and Albert Museum. Work was started in 1923 and the school formally opened by HRH Edward, Prince of Wales in 1924. At the same time he laid the foundation stone for the new Chapel.

The sale of the site at Russell Hill in1961 concentrated the junior and senior education at the Ballards site. In 1968 the school became a fully independent fee-paying school with a separate Trust undertaking the fees for the foundationers.

Extensive changes have taken place in recent years and today there is a thriving IAPS Preparatory School and HMC Senior School on the magnificent one hundred acre estate.