At his instigation an air raid was carried out by British forces from southern France against a German hydrogen factory and zeppelin depot near to the Swiss border.

Granet was subsequently placed on half-pay (retirement) due to the severity of his injuries but returned to duty in 1917 when he was re-appointed as military attaché to Bern.

[11] Granet served in the Second Boer War and was mentioned in dispatches on 2 April 1901 by British commander, Lord Roberts.

[14][15] Granet served with the Army headquarters from 1902 as DAAG and received promotion to the substantive rank of lieutenant-colonel on 9 December 1903.

[17][18] Granet returned to Army headquarters on 17 November 1906 when he was appointed Assistant Director Remounts (i.e. the supply of horses) and promoted to the substantive rank of colonel.

[23] Early in the war he proposed that an air raid be carried out on the German hydrogen factory and zeppelin sheds at Friedrichshafen, near to the Swiss border.

[4] One plane was damaged on takeoff but the remainder survived German AA fire to drop nine bombs on the facility, for the cost of one aircraft shot down and one pilot captured; the remaining pilots returned safely to Belfort and were awarded the Legion of Honour – the aircraft were shipped back to England shortly afterwards.

[4] The hydrogen factory was said to be wrecked and a zeppelin was recorded as probably destroyed, with the raid described by historian Martin Gilbert as a "remarkable feat of aerial initiative".

Whilst in a trench at Lala Baba Hill on 13 August he was badly wounded in the hands and face by gravel from an exploding Turkish shell.