No problem 
To get that node, right click inside the Material Graph and search for scene texture. After selecting the scene texture node you can select the ID in the details panel. Here is a screenshot to help you out.
I was just about to reply and say scrap that i found it, but there is a problem, it seems Scenecolor will now throw up an error and states it can only be used on MaterialDomain = surface … screenshot of the error
It recommends adding postprocessinput0 instead, but i already have 1 of those? not sure what to do now, sorry.
How can you make it so the effect is not showing through walls?
For anyone who stumbles upon this. You can use PostProcess0 now and it works
Great work, I was able to build upon it by making it toggle-able with a material Parameter collection and a special function to be used on characters. Like attached. Seems to work quite well.