Why don't I see the user permissions in the dropdown of my Seller Central account?
This means that you are not logged into Seller Central with the master account. The Seller Central master account is the account you used to create the Amazon Seller account with.
Here are the steps to verify you are logged into the master account:
1. Open a browser window and go to Amazon Seller Central (or you can use these quick links to go directly to the page for .com for .co.uk
2. Sell gear icon on the top right-hand corner then click on Account Info
3. Locate the section under Seller Account Information and click on the button that says Your Seller Profile
4. Here under the various marketplaces under Customer service details, there is an Email that will be displayed which is the master email account.