Planning applications are dealt with by Chichester District Council acting as agents of the South Downs National Park Authority (SDNPA). SIPC are consulted on all applications in the parish. These are considered by the parish council's planning committee at public meetings, after which responses are sent to SDNPA.
Information on planning applications can be viewed through the SDNPA's Public Access system. Enter the planning application reference number into the search box, or search using other criteria, e.g. '16/00334' or 'Stedham'.
A list of the most recent applications considered by the SI Planning Committee and their current status can be found here
SDNPA Local Plan
SDNPA have created a Local Plan which is now open to Public Consultation (26/09/17 - 21/11/17).
Here is the link to the maps for Stedham's entry in the Local Plan (the last section).