Update on this in case anyone encounters a similar issue in Blackboard. After investigation, our VLE experts came up with the following fix:

- After uploading the Adapt SCORM in Bb, go to the 'Advanced Options' for Scorm behaviour.

- In Launch behaviour set the SCO Launch type to Frameset, and the Player Launch type to New window (i.e. reversing what in most cases will be the default).

- Submit/save this change.

After doing this in our Blackboard system the icons appear as the should on IE10/IE11.

Our VLE support team are following-up with Bb to understand why this was happening. If I get an update I'll certainly report back!