Told Porky to have some rest (3,4)
I believe the answer is:
lie down
'some rest' is the definition.
(to lie down is to have a short rest)
'told porky to have' is the wordplay.
I cannot really understand how this works, but
'porky' could be 'lie' (I've seen this in other clues) and 'lie' is present in the answer.
'have' could be 'own' (to have something is to own it) and 'own' is found within the answer.
A single letter 'd' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for lie down that I've seen before include "Put your feet up" , "Relax" , "Become 14" , "Recline" , "Take rest; be submissive (under)" .)