... entering base, head of battalion almost cold and automaton-like (7)
I believe the answer is:
robotic
'automaton-like' is the definition.
(an automaton is a robot)
'entering base head of battalion almost cold' is the wordplay.
'entering base head of battalion' becomes 'robot' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'almost' means to remove the last letter (most of the word but not all of it).
'cold' becomes 'icy' (similar in meaning).
'icy' with its final letter removed is 'ic'.
'robot'+'ic'='ROBOTIC'
'and' is the link.
Can you help me to learn more?
(Other definitions for robotic that I've seen before include "Stiff, unemotional" , "Mechanical; unemotional" , "Using automatic" , "Like a mechanical figure" , "Stiff and emotionless" .)