How do I use Asset place holders in a Post Function

[Dave Gulley]

I am trying to use some of the functionality with placeholders for assets described in this article below in order to try and send an email with some lower level ASSET data which is not shared publicly on the portal

Advanced: Placeholders | Jira Service Management Data Center and Server 5.10 | Atlassian Documentation

I have

1. Created a Custom field with the Asset in "Customers" - This works

2. Set up a Post workflow in a transition to send the email using a "user" field in the asset called "Approvers" - This works and the email goes to the right person or persons

3. Added some placeholders for asset data to return contents of the asset fields. - This doesn't work and I'm obviously doing something stupid/wrong. Can anyone advise who has this working