diff --git a/.env.sample b/.env.sample
index 536e7f69..af236dee 100644
--- a/.env.sample
+++ b/.env.sample
@@ -41,8 +41,7 @@ APIM_INFORMATICA_MAX_REDIRECTS=
 APIM_INFORMATICA_TIMEOUT= # in milliseconds
 
 # ORDNANCE SURVEY
-# Use .uk domain, instead of .co.uk
-ORDNANCE_SURVEY_URL=
+ORDNANCE_SURVEY_URL=https://api.os.uk
 ORDNANCE_SURVEY_KEY=
 ORDNANCE_SURVEY_MAX_REDIRECTS=
 ORDNANCE_SURVEY_TIMEOUT= # in milliseconds
diff --git a/README.md b/README.md
index 0f7e3edc..8dbe732c 100644
--- a/README.md
+++ b/README.md
@@ -155,3 +155,7 @@ The most important prefixes you should have in mind are:
 1. `fix:` which represents bug fixes, and correlates to a [SemVer](https://semver.org/) **patch**.
 2. `feat:` which represents a new feature, and correlates to a [SemVer](https://semver.org/) **minor**.
 3. `feat!:`, `fix!:` or `refactor!:`, etc., which represent a breaking change (indicated by the `!`) and will result in a [SemVer](https://semver.org/) **major**.
+
+### Special notes for .env settings
+
+- ORDNANCE_SURVEY_URL - Domain [https://api.os.co.uk](https://api.os.co.uk) redirects to [https://api.os.uk](https://api.os.uk), so please use [https://api.os.uk](https://api.os.uk).