Hi @rhys,
In general, we recommend a minimum of 3 GCPs to georeference the project. However, I understand that you are using a DJI Phantom 4 RTK that has precise image geolocation, and you would just like to shift the project to the correct location.
Theoretically, it should be possible to use only one GCP but I am not saying this is the recommended way to approach the situation.
The best would be if you place a mininum of 3 GCPs or that you do transform the image geolocation in the output coordinate system as mentioned here:
I hope this helps,