This file is a best fit lookup between output areas (December 2011), electoral wards/divisions and local authority districts in England and Wales as at 31 December 2017. (File Size - 10 MB)Field Names - OA11CD, WD17CD, WD17NM, WD17NMW, LAD17CD, LAD17NMField Types - Text, Text, Text, Text, Text, TextField Lengths - 9, 9, 56, 45, 9, 28REST URL of Feature Access Service – https://services1.arcgis.com/ESMARspQHYMw9BZ9/arcgis/rest/services/OA11_WD17_LAD17_EW_LU_7c8bafd0b45b4244a3f72cae9fb4cbbb/FeatureServer
For more information and an overview of best-fitting follow this link - https://geoportal.statistics.gov.uk/datasets/f0aac7ccbfd04cda9eb03e353c613faa/about