The windows machine is just a stop gap until I can get an RPI to replace it but thank you for the reply.
I can update this thread and say that it does indeed work on Windows having downloaded and installed Python3. I did have to modify the script calibrate_screen.py on line 215 to the following:
# contours.sort(key=cv2.contourArea) - Original line, .sort method not available on tuples
contours = tuple(sorted(contours, key=cv2.contourArea))