diff --git a/etl/README.md b/etl/README.md
index 2c22f46c..fd9427f4 100644
--- a/etl/README.md
+++ b/etl/README.md
@@ -19,7 +19,7 @@ To get the required datasets, you'll need to complete the following steps:
 
 ![](screenshot/AddressBase.png)
 
-4. You should be then able to check out your basket and download the files
+4. You should be then able to check out your basket and download the files. Note: there may be multiple `.zip` files to download for MasterMap due to the size of the dataset.
 
 ## Prerequisites