Thanks for the suggestion. I've just tried it using notepad and that launched fine without having to tick the three checkboxes. Given this, I just went back to my SCCM Remote Control entry and unticked "Active" for Request and Task, saved and it's still working.
I'm totally confused now. It's almost like it needed to be saved once with all three Active checkboxes ticked, but then I can go back, edit it and un-tick these unwanted options - weird.
Not to worry, I guess I must have done something wrong at some point, but it's working now and it's configured as we want.