Some Infopath Fields Not Showing In Sharepoint Form Library Content Type

I have inherited an infopath 2007 form with 240 odd fields. The form was recently updated to include a dozen more fields which have all been promoted.

I am publishing a new version of the form to a Sharepoint 2007 Server (WSS3) site collection using Infopath Forms Services. The Form is set up as a content type on a Forms library. Some of the new fields have shown up in the Library list, but it is also missing some of them.

All the field types are similar (string, check boxes and a few numbers). I thought it was because of restrictions on the amount of column types we can use, and while it seems we are over this threshold, I can manually add new columns to the library (without error) so think I am still within the library limits for types of columns.

I have created a new Forms library, set up the Form as a content type, but the same thing is happening.

I have confirmed the fields are not being created in the sharepoint list, eg: (gl-exportlistfield -fieldinternalname AdditionalEncounterNumber =Field not found)

The data is being captured ok in the submitted / saved form xml

Can anyone provide some information on the best way to discover why these fields are missing when the form content type is set up?

Thanks for looking