Updated NVidia driver. System works well with other games etc.
I tried running in safe mode and force verify. One thing i did notice is that it seems to patch each time it loads and the error logs to me like some sort of permissions issue. So tried running as admin and trying to check Read Write was available on the folder of install.
I was on the Champions forum and it seems to have been a problem over there too... Exact same issue. Would be really nice if Cryptic could have a look at this.