Must be a Paragraph style (Basic Paragraph mostly) style mismatch.
Are there paragraph, character and/or table styles created in your new document? Are there also styles that were created in the document that you are copying from. If there are styles in the original document that have the same names as styles in your new document but have different attributes then the ones in the new document that are different will take precedence and change your content accordingly. If this is the case simply change the names in the new document before pasting in the tables.
Yeah - that's how I've fixed it - deleted all the styles, remade them and reapplied
I don't understand why find fonts couldn't see it though?
Thanks everyone for the response
Yes I'd copied over parts of another document that had styles I'd set up.
However what I got out was neither the style I'd set or the default from the new document. Some of the table looked right but some bits didn't.
Am I expecting too much of the Find Fonts tool?