@mike_backhouse I was able to implement a green screen functionality in Intuiface using a Virtual Webcam like http://sparkosoft.com/sparkocam. However, once you configure the green screen background image in Sparkocam, I haven't been able to switch backgrounds from within Intuiface.
I tried using batch commands and remote controls from within Intuiface to load various Sparkocam presets that would swap backgrounds from inside my XP, but I had limited luck so far.
Something to explore are AHK (https://autohotkey.com/) commands to simulate the manual configuration of the app, and other virtual webcams such as Manycam (https://manycam.com/). If you happen to figure out how to seamlessly swap backgrounds, please let us know.