Hi Tom H,
Thanks for the nodes. This worked fine for me but I did find that at large distances away from world origin, the accuracy of the WorldToScreen and ScreenToWorld became erratic. In my test to replicate the issue (and hopefully fix it after this post), I sat out at roughly -900,000 units. Any movement from the player controller causes the values to jump even when objects are stationary. It feels like super-sensitivity of the values because of the distance. Almost like there is a calculation somewhere in the conversion that uses world origin and the projection distance is creating a wider range of values for equivalent screen space ratio.
I shall play and if I figure it out I will come back and post.