Sailor from China having time on watch (7)
I believe the answer is:
matelot
'sailor' is the definition.
(I've seen this before)
'china having time on watch' is the wordplay.
'china' becomes 'mate' (china plate is Cockney rhyming slang for mate).
'having' says to put letters next to each other.
'time' becomes 't' (abbreviation).
'on' says to put letters next to each other.
'watch' becomes 'lo' (archaic exclamation meaning 'look!').
't' after 'lo' is 'lot'.
'mate' put next to 'lot' is 'MATELOT'.
'from' is the link.
(Other definitions for matelot that I've seen before include "One sailor" , "seafarer" , "Sailor (slang from French)" , "Rating" , "A lot met (anag) - sailor" .)