Sean, my apologies, I never checked Nvidia’s site to see if they have any driver updates. I just used the device manager. I have done an update from Nvidia released on 21/09/2016 and this seems to have resolved the problem. I had with the terrain tools. I will check importing new assets shortly and send you an update.
In the mean time thank you ever so much for taking the time to look into this for me. I will be back in touch shortly to confirm whether the last issue has also been resolved.