Hey there Graham,
Nice detail on the post. This is an issue we are aware of and has to do with some registry settings for IE (which would affect, Chrome, firefox,etc.)
Please follow this link:
I'd make the modifications for both the x32 and x64 this is really meant for the version of the browser you are running vs your OS. The patch, however should already be applied to newer versions just need to make the registry modifications. Also, will need to restart your browser.
Let me know if this fixes the issue.
Michael