My solution
Step 1 - Isolate problem:
I discovered that the problem was with my firewall by disabling it, testing the GET requests again and discovering that they did infact work, this meant my firewall was blocking the port that I was using.
Step 2 - Check what firewall you are using:
my version of openSUSE uses firewalld, and I believe that this is the standard for openSUSE (please correct me if wrong). If you want to check if firewalld is what is installed on your system, run:
sudo systemctl list-units --type=service | grep -E "firewalld"
This should return:
firewalld.service
If this doesn’t appear, your firewall may be disabled or you don’t have firewalld installed.
Step 3 - Understanding firewalld
Documentation for firewalld can be found here.
However this explained it much better.
Step 4 - Fixing the problem
The easiest way to fix the problem is just to disable the firewall. This should only be used if you are on a network with only users that you trust and you’re sure that your router has a firewall (and that it’s any good 
).
You can find which zone your LAN is part of and add the correct port using
sudo firewall-cmd --permanent --zone=<zone> --add-port=<port>/<protocol>.
You can remove the port with
sudo firewall-cmd --permanent --zone=<zone> --remove-port=<port>/<protocol>.
After making these changes you must run firewall-cmd --reload to implement them.
The zone your LAN is part of is most likely the default (most likely public)
I believe it is possible for you to change the zone it is part of, but I’m not sure how.