This issue has been replicated on the following devices:
iPhone X - more common
Objects in the ground plane have a tendency to fall over or resize based on how close the camera is to the plane.
To fix the issue I tried giving the planes ridged bodies and locking their rotation, which worked to an extent but only really on Androids.
With the temp fix above it also just pushes the objects away when moving closer.
The only issue I found like this is: Here
Any suggestions as to how this can be fixed would be much appreciated.