diff --git a/tests/test_sheet_downloader.py b/tests/test_sheet_downloader.py
index 58f471cc..c2b19e97 100644
--- a/tests/test_sheet_downloader.py
+++ b/tests/test_sheet_downloader.py
@@ -38,7 +38,7 @@ def test_init(sheet_downloader):
 
 def test_init_errors(sample_dir):
     test_json = f"{sample_dir}/test_json.json"  # crs changed to EPSG:3857 (note: coordinates are wrong in file)
-    download_url = "https://geo.nls.uk/maps/os/1inch_2nd_ed/{z}/{x}/{y}.png"
+    download_url = "https://mapseries-tilesets.s3.amazonaws.com/1inch_2nd_ed/{z}/{x}/{y}.png"
     with pytest.raises(ValueError, match="file not found"):
         SheetDownloader("fake_file.json", download_url)
     with pytest.raises(ValueError, match="string or list of strings"):
@@ -67,7 +67,7 @@ def test_get_grid_bb(sheet_downloader):
 
 def test_get_grid_bb_errors(sample_dir):
     test_json = f"{sample_dir}/test_json_epsg3857.json"  # crs changed to EPSG:3857 (note: coordinates are wrong in file)
-    download_url = "https://geo.nls.uk/maps/os/1inch_2nd_ed/{z}/{x}/{y}.png"
+    download_url = "https://mapseries-tilesets.s3.amazonaws.com/1inch_2nd_ed/{z}/{x}/{y}.png"
     sd = SheetDownloader(test_json, download_url)
     with pytest.raises(NotImplementedError, match="EPSG:4326"):
         sd.get_grid_bb()