In January 1902 Cobbe was granted the local rank of lieutenant colonel and appointed Commandant of the 1st (Central Africa) Battalion, King's African Rifles, and in this post he deployed with his men to British Somaliland to take part in the Somaliland campaign or the "Mad Mullah War". The Mullah Mohammed Abdullah Hassan, lead clergyman of King Diiriye Guure, had been agitating against British rule in the Somaliland protectorate since 1899 and in 1901 a first British expedition beat him and his Dervish forces and caused him to retreat into the desert interior. However, by the end of the year the Diiriye Guure had recommenced raiding and a second expedition, including Cobbe and his men, was mounted against him. On 6 October, while marching through dense bush at Erigo, the British force was ambushed and then rushed by the Dervishes. Although the north face of the square was pierced and a Maxim gun lost, the Yao Company of the Central Africa Battalion recovered the situation. The Diiriye Guure lost some 700 men and retreated. The British force was not able to continue the pursuit, and returned to Berbera. The Maxim lost during the battle was recovered in the last campaign against Diiriye Guure in 1920, and stands in the Malawi Army’s "Cobbe Barracks" in Zomba, Malawi.