Firepower 4: New Zealand Field Artillery at Gallipoli

In 1911 the NZ Government purchases 18 pounders and 4.5 inch howitzers as it starts to modernise. Their first deployment was to German Somoa, as a part of the Samoa Expeditionary Force, retaking the islands from the Germans. The ANZAC the NZ guns land, howitzers,  on the 26th of April, 1915 and the field guns lands on the 27th. Constrained by lack of suitable firing positions and ammunition, they supported Australian, New Zealand and British across the Gallipoli peninsula.  The withdrawal commenced on the night of the 11th of December and the the last guns were withdrawn on the night of the 19th of December.   What were the key lessons that were learnt?