The situation from 16 April 1941

Brigadier Clowes warned Macky that it was critical that they be able to hold the "gorge" until 19 April 1941. He also told Macky that support would eventually arrive. He also ordered Macky to sink the ferry boat once all of his men were across. 

The priority was to hold the western end of the gorge/ Macky was told that it was especially important to defend the high ground in the north. 

The "first moves ordered were intended to put the 6th Australian Division troops behind the passes on 16 April.

General Freyberg was a personal friend of Churchill, and Churchill had complete confidence in Freyberg. It is unclear that he was actually capable of performing the task of commanding the withdrawal. 

The New Zealand 5th Brigade was the initial rearguard force. In additiion to the 5th New Zealand Brigade, you had the 6th New Zealand Brigade group, and the left flank guard of the 6th Australian Brigade Group. 

The British armored brigade "covered the withdrawal across the plains of Thessaly." This is based on the account in "Greece, Crete, and Syria" by Gavin Long.