Wards Map

For the dataset, I simply used Get Data / Power Query and pointed it to the icitw_wgs84.json file as a source. You could use that as a starting point and join your own data to it, or you could import your own dataset that contains ward data and use Power Query to create a column that matches the ward name + number from the JSON file.

For the first route where JSON is used as the source, here's a sample query:

let
    Source = Json.Document(File.Contents("C:\[...]\icitw_wgs84.json")),
    objects = Source[objects],
    icitw_wgs1 = objects[icitw_wgs84],
    geometries = icitw_wgs1[geometries],
    #"Converted to Table" = Table.FromList(geometries, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
    #"Expanded Column1" = Table.ExpandRecordColumn(#"Converted to Table", "Column1", {"arcs", "type", "properties"}, {"Column1.arcs", "Column1.type", "Column1.properties"}),
    #"Expanded Column1.properties" = Table.ExpandRecordColumn(#"Expanded Column1", "Column1.properties", {"GEO_ID", "CREATE_ID", "NAME", "SCODE_NAME", "LCODE_NAME", "TYPE_DESC", "TYPE_CODE", "OBJECTID", "SHAPE_AREA", "SHAPE_LEN"}, {"Column1.properties.GEO_ID", "Column1.properties.CREATE_ID", "Column1.properties.NAME", "Column1.properties.SCODE_NAME", "Column1.properties.LCODE_NAME", "Column1.properties.TYPE_DESC", "Column1.properties.TYPE_CODE", "Column1.properties.OBJECTID", "Column1.properties.SHAPE_AREA", "Column1.properties.SHAPE_LEN"}),
    #"Removed Columns" = Table.RemoveColumns(#"Expanded Column1.properties",{"Column1.arcs", "Column1.type", "Column1.properties.GEO_ID", "Column1.properties.CREATE_ID"}),
    #"Renamed Columns" = Table.RenameColumns(#"Removed Columns",{{"Column1.properties.NAME", "Ward Name"}, {"Column1.properties.SCODE_NAME", "SCODE NAME"}, {"Column1.properties.LCODE_NAME", "LCODE NAME"}, {"Column1.properties.TYPE_DESC", "TYPE CODE"}}),
    #"Removed Columns1" = Table.RemoveColumns(#"Renamed Columns",{"TYPE CODE", "Column1.properties.TYPE_CODE", "Column1.properties.SHAPE_AREA", "Column1.properties.SHAPE_LEN"}),
    #"Renamed Columns1" = Table.RenameColumns(#"Removed Columns1",{{"Column1.properties.OBJECTID", "Object ID"}})
in
    #"Renamed Columns1"