Yes: in fact most of the British Army's senior officers from Lord Kitchener downward recognised that the idea of "over by Christmas" was wishful thinking in the extreme. This in fact motivated Kitchener's recruiting policy. As Secretary of War he was determined that Britain's New Armies be husbanded and trained to the highest possible standard away from France, and only committed to the field around 1917, when he reckoned Germany would have been suitably attrited by fighting with the French and Russians and the Royal Navy blockade. In the event, political considerations meant that was impossible: it was seen as abandoning France and making them shoulder the greatest burden of the fighting while German soldiers occupied their soil. Hence the New Armies were committed early, leading to their severe blooding on the First Day on the Somme in 1916.

Sources:

Gordon Corrigan, Mud, Blood and Poppycock

Simkins, Jukes and Hickey, The First World War: The War to End All Wars