It is an official document. It is spilt up in regions and the one which the Sutton Loop is in is the Kent, Sussex & Wessex Region. https://sacuksprodnrdigital0001.blob.core.windows.net/sectional-appendix/Sectional%20Appendix%20full%20PDFs%20December%202022/Kent%20Sussex%20Wessex%20Sectional%20Appendix%20December%202022%20.pdf