One didn’t have to run this bye? (8,5)
I believe the answer is:
optional extra
'one didn't have' is the definition.
I know nothing about this answer so I can't judge whether this works.
'run this bye?' is the wordplay.
'run' becomes 'optional' (I can't explain this - if you can you should believe this answer much more).
'this bye?' becomes 'extra' (I have seen 'A bye' mean 'extra' so perhaps 'bye' could also mean 'extra').
'optional'+'extra'='OPTIONAL EXTRA'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for optional extra that I've seen before include "Non-obligatory addition" , "It would be nice to have" , "Non-standard feature" , "Non-obligatory item" , "Non-essential additional item" .)