rowid,zoom_level,tile_column,tile_row,tile_data
7,6,31,42,http://datasette-tiles.staging.planning.data.gov.uk/battlefield/tiles/7.blob?_blob_column=tile_data
9,6,32,42,http://datasette-tiles.staging.planning.data.gov.uk/battlefield/tiles/9.blob?_blob_column=tile_data