Thanks Greg, now deleted 6773 tags! You were absolutely correct with your diagnoses and I have unchecked the box you suggested.
As a supplementary is it safe to delete tags that are still showing with numbers or will tat delete the item that is tagged?
It is safe to do that as long as the documents are also located somewhere else in the database. I’ve seen a few people over the years post here that they file the documents directly in the tags, so in those (rare) cases the document would be deleted if the tag was deleted.