Thank you Phil Read!
That worked, so the solution for me was ensuring a still image file was loaded in under appearance with 0 offsets and a graphics surface pattern set to the size of my screen in this instance 1660 x 935mm (no need for units as it will automatically pick up on this from project) which you must then align to the boundaries of your screen.
Then under the identity tab in the material browser I entered my file path and file name with the x and y sizes which i had to use a bit of trial and error to get it right.
This is what i entered in for my video path:
[video:<path>|<X>|<Y>|<rotation>]