A ranar 20 ga Fabrairun 1741, an ba shi mukamin brigadier janar, kuma an tura shi zuwa Jamus tare da rundunar sojojin Burtaniya a cikin Yaƙin Nasara na Austriya. Ya yi yaƙi a
Yaƙin Dettingen a ranar 27 ga Yuni, 1743, kuma daga baya aka daukaka shi zuwa babban janar a ranar 13 ga Yuli. A ranar 30 ga Afrilu, 1745, Onslow ya gaji Viscount Cobham a matsayin colonel kuma kyaftin na 1st Troop of Horse Grenadier Guards, yayin da Edward Wolfe ya karbi ragamar Sarki. Shi da Henry Hawley sun yi umurni na biyu na doki a yakin Fontenoy. Ya kasance daya daga cikin janar din da ke London a watan Nuwamba bayan da aka sake kiran sojojin Birtaniya a Flanders don murkushe Jacobite na 1745.