There are quite a lot of descendants of the Cadmans around the Island.
Henry Cadman "late president of the Yorkshire Anglers' Association" published his memories of Manx angling in 1898 under the title "Harry Druidale" (London, Macmillan) This volume had 13 illustrations of Manx scenery.
There is a large professional pedigree of the family somewhere around, taking them back a long way. I recall a relationship with the forfeited de Derwentwaters.