Sorry. My main point was regarding FitzHerbert Walk. OSM has wrong capitalisation as Fitzherbert. When it is FitzHerbert.
Regarding Hanwell Island. I have not seen any reliable references to a Hanwell Island name at this locale. Please provide links.

Also of note is that GoParks, the referenced source of the data, is itself in error (I have contacted them and they have agreed they have incorrect naming).

Hanwell Island is not an offical name for the landmass in the Brent river at this locale. There is no official name for it. I have also noted that GoParks have incorrectly named (as does OSM) FitzHerbert Walk (without the capital H). Please see Google Maps photos for offical signage of this locale and nameingof the Walk.