Should that be so, where is it packed? (2,5,4)
I believe the answer is:
in which case
'should that' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'so where is it packed?' is the wordplay.
I cannot quite see how this works, but
'so' could be 'as' (I've seen this in other clues) and 'as' is located in the answer.
'where' could be 'inwhich' (synonyms) and 'inwhich' is found in the answer.
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is located in the answer.
A single letter 'c' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
'be' acts as a link.
Can you help me to learn more?