Foreign key not showing in database diagram or table

I am trying to migrate my database to Dataverse but have hit an issue...

I have 2 tables, Stocks and OrderDetails which are related many to 1.

However, when I look at either table I cannot see the foreign key column.

The relationship is showing in the Keys on the table:

The database diagram shows this:

The application built on this database is able to use the relationship so it is working somehow.

Any ideas how I can get the tables to actually show the related ID so that I can export to Dataverse?

Many thanks