Richard,

If you bother to read, you will see that the

The Treaty of Sèvres (10 August 1920) was the peace treaty between the Ottoman Empire and Allies at the end of World War I. The Treaty of Versailles was signed with Germany before this treaty to annul the German concessions including the economic rights and enterprises.
The treaty had four signatories for the Ottoman Empire: Rıza Tevfik, the grand vizier Damat Ferid Pasha, ambassador Hadi Pasha and the minister of education Reşid Halis who were endorsed by Sultan Mehmed VI.
Of the Principal Allied powers it excluded the United States. Russia was also excluded because it had negotiated the Treaty of Brest-Litovsk with the Ottoman Empire in 1918. In that treaty, at the insistence of the Grand Vizier Talat Pasha, the Ottoman Empire regained the lands Russia had captured in the Russo-Turkish War (1877–1878), specifically Ardahan, Kars, and Batumi. Sir George Dixon Grahame signed for Great Britain, Alexandre Millerand for France and Count Lelio Bonin Longare for Italy.

This is a valid treaty. Turkey did not accept it.Thus,

"The Treaty of Lausanne was a peace treaty signed in Lausanne, Switzerland on 24 July 1923, that settled the Anatolian and East Thracian parts of the partitioning of the Ottoman Empire.[1] The treaty of Lausanne was ratified by the Greek government on 11 February 1924, by the Turkish government on 31 March, and by the governments of Great Britain, Italy and Japan on 6 August. It was registered in the League of Nations Treaty Series on 5 September 1924.[2] The Treaty of Lausanne superseded the Treaty of Sèvres which was signed by representatives of the Ottoman Empire.

If the Turks did NOT have standing, the first treaty applies, If they DO have standing, the second applies. IN EITHER CASE, Mandate Palestine was declared to be the Jewish homeland,

"The Mandatory will be responsible for putting into effect the declaration originally made on November 2, 1917, by the British Government, and adopted by the other Allied Powers, in favour of the establishment in Palestine of a national home for the Jewish people"