I understand that categories are the main subgroups and tags give more detail about a post's content, and that duplication can cause technical and SEO problems.
However, can someone clarify the right way to go in this scenario: the category is Northumberland News and the post is about some news in Northumberland National Park, so the tags would include Northumberland National Park. In some instances two organisations, each with the word Northumberland in their formal title, work together, so there could be one post with a lot of Northumberland and therefore two or more tags with the word Northumberland, eg Northumberland Wildlife Trust, Northumberland National Park, etc as tags.
Will this cause problems? If so, what would you suggest? Dropping the word Northumberland from the tags, and just having wildlife trust, national park, etc?