Rolled back to IE9 and it's working OK. Working my way back to at least IE10 so I can access XML feeds via https (previous versions M$ the source code with bloated css/html)
Got to IE10 and it's working. The other thing I noticed is that the HTML5 compatibility check on that site fails in the webviewer but not in the browser. That shouldn't worry me as we don't send files over 2gb via Filemaker. Not sure if there's a browser setting related to this or whether it's Filemaker causing IE to run in a particular mode.
OK, that got weird. Was collecting info for reporting this as an issue when IE11 started working??? A bit more investigating and it's a site-specific issue, although I'm not sure what that issue might be. Thought it might have been the combination of IE11, Flash and https, but https://www.adobe.com/au/downloads.edu.html works fine. Contacting the site to investigate