For putting the space in there, there's another place in that file where the function is called with no argument (set_input_prompt()). It looks like that should result in a prompt with a gap[ ].

I'm not sure what you mean about other cells running but not executed?

Got it! Ah so I thought that if I ran multiple cells at once then the other cells wouldn't be affected, but it turns out they are so it's all good!

Thanks@danagilliann, this looks good to me.