Note that downgrades will fail of such data is present

As there is no unknown building type reclassifying is impossible

migrations/023.garden_buildings.down.sql

@@ -1,2 +1,3 @@
+-- note that you need to somehow reclassify such buildings, if present - before downgrading
 DELETE FROM reference_tables.landuse_classifications WHERE landuse_id = 'U071X';
 DELETE FROM reference_tables.buildings_landuse_group WHERE landuse_id = 'U071X';

migrations/024.unclassified_buildings.up.sql

@@ -1,3 +1,5 @@
+-- note that you need to somehow reclassify such buildings, if present - before downgrading
+
 -- equivalent to 015 migration
 INSERT INTO reference_tables.landuse_classifications
 (landuse_id, description, level, parent_id, is_used)