Hi DannRees,
I sincerely apologize for not responding sooner. What version of the Engine are you using, and are you using one that you built from source code, or installed by the Launcher?
Are you able to make this happen using one of the project templates? If so, could you please let me know exactly how you set everything up so that I can reproduce the issue here?
In your other post on this issue, you mentioned you were trying to make this work on a Galaxy S4. Have you tried reproducing the issue on a different Android device?