Make mark in completion of list, say, with ‘Henry’ (4)
I believe the answer is:
etch
'make mark' is the definition.
'etch' can be an answer for 'mark' (I've seen this before). I'm not certain of the 'make' bit.
'completion of list say with henry' is the wordplay.
'completion of list say' becomes 'etc' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'with' means one lot of letters go next to another.
'henry' becomes 'H' (symbol for the unit of electrical inductance).
'etc'+'h'='ETCH'
'in' is the link.
Can you help me to learn more?
(Other definitions for etch that I've seen before include "Imprint vividly" , "Draw on metal with acid" , "Chase" , "Carve into metal with acid" , "Engrave (metal, glass etc.)" .)