Quantity of claret following punch? (9)
I believe the answer is:
nosebleed
'claret following punch?' is the definition.
I know that 'claret' relates to this answer.
'quantity' is the wordplay.
I cannot really see how this works, but
'quantity' could be 'nose' (nose is a kind of quantity) and 'nose' is present in the answer.
The remaining letters 'bleed' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'of' acts as a link.
(Other definitions for nosebleed that I've seen before include "Result of a punch on the schnozzle?" , "Epistaxis" , "Outpouring from snout" .)