Last snifter near Deal, heading north (8)
I believe the answer is:
nightcap
'last snifter' is the definition.
(snifter can mean a small drink)
'near deal heading north' is the wordplay.
'near' becomes 'nigh' (synonyms).
'deal' becomes 'pact' (I've seen this in another clue).
'heading north' says the letters should be written backwards.
'pact' in reverse letter order is 'tcap'.
'nigh'+'tcap'='NIGHTCAP'
(Other definitions for nightcap that I've seen before include "Pre-bed drink" , "Head covering" , "late evening beverage" , "Bedtime tipple" , "drink having sleepy effect?" .)