Go to the Search page. Type in a place-name in the search box or zoom/pan the map window. Thumbnail images and metadata information will appear in the right sidebar showing the search results (this list will automatically update as you change the view in the map window).
Click on the map record that interests you in the search results and you will see the full metadata information we hold for that map record.
Click on the link in the metadata to go straight to view the old map.