Colour PMS just wont go away

Hi I am having a colour issue only in one file.

I have a PMS colour in indesign I would like to delete or replace with black.

There are no links in the document.

I have done a find and change of the pms in the document and 0 instances have been found.

I have turned on separation preview and nothing.

Nothing on Master pages

There were instances in the paragraph styles which I now have deleted.

Why can I not delete this swatch or change it to another colour?