The Church of England Research and Statistics unit has shared a parish mapping tool which allows you to look at parish boundaries and also relevant statistics for the area.
The tool can be found here: http://arcg.is/00ieuz and is linked to from the Research and Statistics web page: https://www.churchofengland.org/researchandstats
The map shows parishes, churches, schools, and ecclesiastical boundaries. Each parish has census and deprivation information attached.
• Parish boundary data on the map are updated periodically, typically every 6 months;
• Census statistics are from the 2011 census;
• Deprivation statistics are from the 2015 indices of multiple deprivation;
• School locations are from the Department for Education’s public database.
For census and deprivation statistics, updates consist of mapping the datasets onto the latest parish boundaries (which change periodically as parish reorganisations take place). The map uses the ArcGIS mapping platform, http://www.arcgis.com/index.html. The map is public and free to use. It can be edited to show different things in different ways. Anyone who wants to register for a free public account can do so which will allow them the save their changes and add their own data.