Custom attributes not appearing on single page

I have a custom listing type, I have created a custom attribute (Phone Number), in the “Attribute” tab (where it says “Add new attribute”).

I go to the “Single Page” tab, and add in my Phone Number field from the “General” box on the right. Press the green Update button, then press the default blue update button too.

I add a new listing and fill in the Phone Number field and save.

When I view the single page on the front-end, the Phone Number isn’t showing.

This happens with all custom attributes I’m adding. Everything else shows up as expected in the layout I’ve created (title, location, description, features etc).

I have also tried putting my attribute in an Attribute Box (which is in the Basic box on the right when editing Single Page). I’m not sure what that’s for but not work either.

Any advice?