On Scotch bottles they are recuperating (2,3,4)
I believe the answer is:
on the mend
'recuperating' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.
'on scotch bottles they' is the wordplay.
'scotch' becomes 'end' ('scotch' can mean to put an end to something).
'bottles' is an insertion indicator (bottle can mean to contain).
'they' becomes 'them' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'on'+'end'='onend'
'onend' enclosing 'them' is 'ON THE MEND'.
'are' is the link.
Can you help me to learn more?
(Other definitions for on the mend that I've seen before include "Making recovery" , "Improving in health" , "convalescing" , "Looking up" , "undergoing recovery?" .)