Have you managed to trace the family any further forward?
I can't find Louis jnr in the 1841 census 
I have information on Louis in New Zealand to most of his present day descendants.
I am trying to trace him back and especially his father's roots in France. From what I understand his father JLM Hetet was a French prisoner of war in England. He left Louis and his mother Mary and went/was released back to France. Louis, as a teen, was sent to Mary's father. Just looking at the Census Mary's family appear to be grocers.
It is thought by the family in NZ that Louis came out here c1830-40 on a whaling? ship, returned to England? and came back to settle in NZ. So that would explain why Louis doesn't show in the 1841 Census he would have been in/on his way to NZ.
Regards
Yvonne