Ramba uchinyora ndima iyi - Cassels akashanda muHondo Yenyika II, kwaakanga achishanda muEngland, uye akapinda kosi yakapfupikiswa paStaff College, Camberley. Muna Chivabvu 1940 akazove brigade major neTerritorial Army (TA) unit, 157th Infantry Brigade, yaitungamirwa naBrigadier Sir John Laurie, aimbova Cassels's Commanding Officer (CO) mu2nd Seaforths, chikamu chaMajor General James Drew's 52nd (Lowland) Infantry Division, iyo yakatumirwa kuFrance muna Chikumi 1940 kuti isimbise mauto eFrance mushure mekubviswa kweBritish Expeditionary Force (BEF) kubva kuDunkirk. Boka raCassel, rokutanga pamabhuroka eDhivhizheni yechi52 kusvika muFrance, rakarayirwa, nokukurumidza mushure mekusvika kwaro, kuumba kurudyi kweFrench Tenth Army paConches, Normandy. Zvisinei, mamiriro ezvinhu akaonekwa seasina tariro uye brigade yaCassel yakazobviswa kuburikidza neCherbourg musi wa18 Chikumi. VaFrench vakasaina chibvumirano chechipiri cheCompiègne
mazuva mashomanana gare gare.