Custom Fields used for Participants and then used in a Profile are not displayed

I have created specific custom fields for Participants. These are viewable in Preview mode under Custom Data.
When these fields are used in a Profile they are not displayed in Preview mode.

I notice that the Profile I have created does not have anything shown in the "Type" column – whereas all the other profiles do have an entry – such as "individual, Contact". I cannot see where this "Type" entry is derived from when creating the profile. If its the Field Type (from the Custom Field) – then its not linking to Participants nor Events.