Ok maybe the DB isn't the issue. Sometimes the site works partially now I have manually reset the site url.
I can see in chrome dev tools that 2 folders are being prepended to the actual file path for wp-content - it is prepending the folder structure from the live site (i.e should be example.dev/wp-content - is example.dev/staging/example/wp-content).
Any help appreciated. I have done a find in folder searching for "staging" but it's not present apart from in installer-backup.php. htaccess doesn't contain it. I've updated the permalinks (manually resetting the site-url in wp-config allowed me to log in to do this (intermittent)).