Scrap this question completely. The issue was that we were using the Latest Feed widget, rather than the Recent Media widget.
N00b.
We were only using the widget and hadn’t embedded it in any pages / posts so I don’t think that was the problem. It looks like an issue with the user account API client ID and userID being cached in the database and not overwritten when the user is changed, but I can’t say for certain.
We couldn’t work it out, so ended up using a different plugin in the end as we had to make the site live 🙁
I’m afraid not. We used a different plugin in the end.
Interestingly, I’ve just disabled the minify JS section of the W3 Total Cache plugin and it appears to be working.
I would guess that minifying the JS is not compatible with the JS code you have in the plugin. It might help you work out what could be causing it.
Thanks.