Coates became the representative of the Palestine Memorial Committee in London, raising funds from friends of the Egyptian Expeditionary Force to build a cenotaph in Palestine in memory of those who had fallen in battle. In December 1919 Lord Treowen criticised the proposed design and site of the memorial as a desecration of the Mount of Olives; Coates defended the choice of both and referred Treowen's letter to Field Marshal Lord Allenby. Treowen responded by questioning Coates' methods as not those which carry conviction or inspire confidence. Coates then corresponded privately, and persuaded Treowen to retreat and state that he was not motivated by any personal feelings against Coates.