Bayham Abbey sites on the Kent Sussex border. The impressive ruins, built from golden local sandstone, include the 13th to 15th-century church, the chapter house, and a picturesque 14th-century gatehouse. Do check English Heritage (link to https://www.english-heritage.org.uk/visit/places/bayham-old-abbey/ ) before planning a visit to check it is open. The only way to see it might be by hot air balloon over Kent.