How do you protect a LibreOffice Writer form yet allow the form fields to be used?

Hopefully the last one!

I have created my form in Writer. It contains a mixture of text and form fields.

I would like to protect the text from being accidentally overwritten but still allow the users to use the form fields.
The idea is that they would receive a blank copy as a template, fill it in and save it under a new file name but I don’t want them accidentally removing or moving parts of the form, or otherwise tampering with it.

Is it possible to do this?
If I set the document to open as Read-only then the check-boxes and drop-downs in the form fields are disabled as well. I can’t see how to protect the text whilst leaving the form fields unprotected.

I have looked in the user guide https://wiki.documentfoundation.org/images/1/15/0215WG3-UsingFormsInWriter.pdf but it does not seem to correspond with what I am seeing on my screen.