Thanks all, thats a good idea, i’ll try rolling back to cc2104 and using EXR’s with layers, as far as i can run the work flow through in my head it should work!
using export frame to Photoshop works perfectly.. except for the fact that it requires you to export each frame manually which is obviously not a sensible option when you have 10s of thousands of frames to export. as mentioned above it really frustrating as the functionality ids there just not the automation which you’d expect given the relationship between the two programs.