Thanks Golam!
I was looking over YT videos of guys showing theirs off to see what they were doing different, and I found the answer 
See the attached photo for the difference in wiring. I took the D and C connections, and just moved them onto their own lines on the breadboard (from C to B and A respectively)... this has allowed it to run through the test simulation with no errors. Also note, there is now a resistor from 5V to breadboard then breadboard to + on the display. I have just tried it without the resistor and it does not work.
I figured I should post this so that anyone in my position may have help... is there a way to put this issue as "solved"?
Thanks,
Titchboi
