St Moluag's Cathedral, Lismore
Argyll and Bute, United Kingdom · built 1300
St Moluag's Cathedral is a church located on the Scottish island of Lismore just off the coast of Oban. Despite its name it is no longer a cathedral as it is a church of the Church of Scotland. The present-day parish church of 1749 stands on the site of the choir of the abandoned 13th-century cathedral, incorporating much of its material, but wrapped in 18th-century design.
Cathedral data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).