Hi Rory!!
I tried it once, on your old V2 now my X8,
seemed pretty cool. I engaged it while in forward flight and then banked to the left, it for sure combined roll and yaw, so yes it works.
However I was moving slowly laterally not in IOC or "bank turn" and then switched to "banked turn" it twitched hard and pulled to the left and up, I then flipped off IOC and all was ok. So perhaps I will try again while already in forward straight flight. It was pretty cool to do the bank turn with one hand though..