A watan Mayu na 1919, "Marlborough" ya gudanar da gwaje-gwaje tare da sabbin harsasai masu fashewa na inci 6 daga Kerch Peninsula, kodayake waɗannan sun tabbatar da rashin aminci. A wannan lokacin, ta yi amfani da balloon kite don taimakawa wajen gano faduwar harbi. Daga baya wannan watan, wani harsashi ya fashe a cikin barikin hagu na "A" turret kuma ya haifar da ƙananan lalacewa. Yayin da yake tsaye a gabar tsibirin Kerch, jirgin ya ba da tallafin bindigogi ga sojojin White, gami da harbe-harben wuraren Bolshevik a ƙauyukan Koi-Asan da Dal Kamici. A shekara ta 1920, hankalin Birtaniya ya juya zuwa yakin Girka-Turkiya. A ranar 20 ga Yuni, 1920, "Marlborough" ya isa Constantinople, inda aka mayar da hankali ga rundunar jiragen ruwa na Rumunan don tallafawa
mamaye birnin. A ranar 6 ga Yuli, sojojin Burtaniya sun sauka a Gemlik, yayin da "Marlborough" ke ba da tallafin bindiga.