I'm afraid it seems to me the 1881 sighting was not your Louis but another Louis, for the reasons already given.
His birthplace was consistently Newcastle in all censuses 1881 onwards. Although he used the name Louis Henry in the censuses, his full name was given as Louis Aaron A H Cohen when he married Miriam Hilda Maude Collins in Fulham in Jun qtr 1900.
Birth: Mar qtr 1875
Louis Aaron A Cohen
Newcastle upon Tyne 10b 93