When the invasion began on 6 June 1944 Bols did not participate directly, being retained at the War Office as a staff officer, but, in early July, he was given command of the 185th Infantry Brigade, part of the 3rd Infantry Division under Major General Lashmer "Bolo" Whistler. He led the brigade during the final stages of the Battle for Caen, where it saw heavy fighting in Operation Charnwood, Operation Goodwood, and Operation Bluecoat and later in the Allied advance from Paris to the Rhine. He was appointed a Companion of the Distinguished Service Order (DSO) for his command of the brigade during the Battle of Overloon and the subsequent liberation of Overloon and Venray in the Netherlands; the recommendation for the award of the DSO makes particular mention of the achievement of the brigade in forcing the River Breek despite heavy resistance, poor weather and shortage of assault equipment. The award was gazetted on 1 March 1945.