Pub grub that's eaten between drills? (15*)
I believe the answer is:
'eaten between drills?' is the definition.
I know nothing about this answer so I can't judge whether this works.
'pub grub' is the wordplay.
I cannot really see how this works, but
'grub' could be 'lunch' (lunching is a kind of grubbing) and 'lunch' is present in the answer.
This explanation may well be incorrect...
'that's' is the link.
Can you help me to learn more?
(Another definition for ploughmanslunch that I've seen is " meal".)