I researched several approaches and investigating the mapping library to be used within WordPress. Whenever a JSON is used in a project, the data has to be analysed and verified that we don’t need any other data from a different in order to be able to create a meaningful map.
The map of England in GeoJson format was found and we were then able to create the WordPress page.
For this particular implementation we didn’t want to hold the data in the database. We do a call each time the user selects a different petition to view. However we could add the petitions into the database, creating a custom post type, running an import on a regular basis via a cron job. This would then lend itself to potential organic traffic if we also considered the meta data when we imported it.