A best fit lookup between 2001 Output Areas (OA) and built-up area sub-divisions (BUASD) and built-up areas (BUA), local authority districts (LAD) and regions (RGN) as at 31 December 2011 in England and Wales. (File size - 6MB)Field Names - OA01CD, BUASD11CD, BUASD11NM, BUA11CD, BUA11NM, LAD11CD, LAD11NM, LAD11NMW, RGN11CD, RGN11NMField Types - Text, Text, Text, Text, Text, Text, Text, Text, Text, Text, Field Lengths - 9, 9, 44, 9, 50, 9, 28, 24, 9, 24REST URL of Feature Access Service – https://services1.arcgis.com/ESMARspQHYMw9BZ9/arcgis/rest/services/OA01_BUASD11_BUA11_LAD11_RGN11_EW_LU_676cc8263c234846985de6a5a1ab967a/FeatureServer
For more information and an overview of best-fitting follow this link - https://geoportal.statistics.gov.uk/datasets/f0aac7ccbfd04cda9eb03e353c613faa/about