Lad stows aboard Victory with time for quayside farewell (3,6)
I believe the answer is:
bon voyage
'farewell' is the definition.
(bon voyage is a kind of farewell)
'lad stows aboard victory with time for quayside' is the wordplay.
I cannot quite understand how this works, but
'aboard' could be 'on' (eg on a ship or train) and 'on' is located in the answer.
'victory' could be 'v' and 'v' is found within the answer.
'lad' could be 'boy' (lad means a young boy) and 'boy' is found in the leftover letters.
'time' could be 'age' (an age is a period of time) and 'age' is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for bon voyage that I've seen before include "Have a good journey - at sea" , "Have a good trip - on the briny" , "Have a nice cruise, monsieur" , "travel well!" .)