Thanks, that worked.
BUT Two items of feedback:
(1) It would be good if there was a notification or at least something showing in the applications listing so it was easy to know when apps were out of date.
(2) I then checked and found that the Blog app for Groups and also for Events were also out of date on our site, but on downloading them it seems the download file is called 'blog'zip' for all of them! Perhaps renaming them to event-blog.zip, page-blog.zip etc would be better
As a PS, I find it remarkable that an app who's only function is to display a list of blogs on a page could have a bug that stopped it doing that one task - how on earth do you test things?!!