There is no 4GB model. This thread has explained that you have an 8GB model and why you have as much space as you do. My 8GB Moto G (non-LTE) also says 5.52GB 'Total space.' The phone allocates 5.52GB for you to use, the rest is kept separate for Android. If you wiped all partitions on the phone, you would then have close to 8GB.
You always have the option of rooting and deleting some system apps to free up more space.
I was already aware of the reasons for memory usage but just not this much. That's why I've asked for someone with the exact same model to confirm that my case is normal.
Also, could anyone point me in the right direction for why the 4.4.4 update isn't available for me? I'm in the UK.
EDIT: I've just seen that you've edited your last post. Thanks