Where absolutely necessary answer cheers press (2,1,4)
I believe the answer is:
at a push
'where absolutely necessary' is the definition.
I don't know anything about this answer so I can't tell whether this works.
'answer cheers press' is the wordplay.
'answer' becomes 'a' (abbreviation eg in Q and A).
'cheers' becomes 'ta' (I've seen this in other clues).
'press' becomes 'push' (pushing is a kind of pressing).
'a'+'ta'+'push'='AT A PUSH'
Can you help me to learn more?
(Other definitions for at a push that I've seen before include "If a big effort were made - say a shove" , "If really necessary" , "With difficulty" .)