Within one month of the Battle of Messines the Division had been rested, assisted the First French Army in the north on the work of constructing gun positions and making roads and then reoccupied their old positions about Ploegsteert. But the time was not conflict free, "the storm clouds about Ypres had banked up solidly. The activity of aeroplanes and guns was already marked, and all the countless preparation for the continuance of the battle, to which Messines had been the overture, were approaching completion. A tremendous concentration of troops was gathering in the Ypres flats."


The 24th of July heralded Division's more aggressive role. This embraced 3 tasks. In the first place, to make the feint against Lille they would establish one or two forward posts commanding the river and dig on its banks isolated trenches intended, not for occupation, but to convey the impression of being designed to cover the construction of bridges and the crossing of the river. Secondly, they aimed at the capture and occupation of Basseville. Lastly, they proposed to raid the enemy's posts north-east of the village among the hedgerows and to advance their line in this neighbourhood.


The initial attempt to capture Basseville failed and was where McLean was awarded the Military Cross, Devery and Vestey the D.C.M. The participating regiments were exposed to the German flammenwerfer and mustard gas.  L.-Cpl. Leslie Wilton Andrew also earned the Victoria Cross. 


On the 31st of July, the role allotted to the Division was again, as on the 27th, three-fold: the capture and holding of Basseville, the clearance of the hedge system 500 yards to the north of the village combined with an advance of our posts, and the raiding of the enemy's position between our front and the railway on the extreme left towards the Douve. Around the 31st these were achieved. 





Immediately across the Douve the 3rd Australians had been equally successful in capturing the enemy's line of posts along the road from Warneton to Gapaard. In the north, the left wing of the Second Army had pushed astride the Ypres-Comines canal, and Hollebeke and Klein Zillebeke were after 3 years' interval once more in British hands. Earl Johnston was killed by a sniper and Pennefather earned a D.C.M. 

Our own guns were even more aggressive than the German. Warneton Deulemont and other villages were reduced to heaps of ruined roofless walls, gaps in which revealed the more substantial concrete dugouts which they screened. Co-operation was given to the attacks in the north, particularly to that of 16th August on Langemarck, by artillery and machine gun barrages and violent counter-battery activity. Frélinghien also was on that date drenched in gas and liquid oil.

While about Basseville both artilleries remained active, there was now little infantry fighting. Both sides were engrossed in consolidation. A single effort at a raid by the Germans was summarily repulsed. Our patrols, however, were continually active towards Warneton, along the Lys and down the Douve valley, where some encounters took place with enemy parties. Over the Lys the enemy made no attempt to throw bridges or force a crossing, and aggressive sniping by our patrols denied him the right of moving freely in front of his own lines on the southern bank.

From these staging billets the Division, less the artillery and the Rifle Brigade, proceeded by train at the end of the month to the Second Army reserve area at Lumbres in the valley west of St. Omer. Units were accompanied by their travelling kitchens and water carts, but the remainder of the transport trekked by road. The last of the artillery moved out of the line on 6th September and rested for a few days in the neighbourhood of Morbecque, whence they presently rejoined the Division. The rifle Brigade was left in the forward area for work on cable communications under the orders of the Second army. At the end of August the 4th Australian Division was relieved by IX. Corps troops and transferred to I. Anzac. Thereupon II. Anzac Headquarters handed over the command of their sector to the VIII. Corps and moved to Lumbres.