Geocode data missing from activities.list

I'm trying to use the https://developers.google.com/+/api/latest/activities/list call to get information about my public posts. It's all working fine except for location information. The top post (https://plus.google.com/+JulianBond23/posts/1Ebwhstbm92) has a geolocation attached, 51.814888,-0.02532 the post does get returned but there's no geocode field in the returned JSON. As far as I can see all my location settings are set to public.

Any ideas why the geocode (and possibly address) data is missing?