I went on this route and was told in training whenever you see a large white right or left arrow painted on the road you have to signal left or right is this the correct procedure as I am confused at mini roundabouts as the road goes sort of straight ahead, however signalling right could confuse oncoming drivers.
Generally speaking, there is NO need to signal when large arrows designate the direction for your lane. But signalling will not normally be a problem either.
But the rule doesn’t apply at roundabouts except huge ones. This is because traffic approaching the roundabout wont have a clue where you’re heading as they cant see the road marking. So its worth a signal.
I agree with ROG in the case in the link. Given that you will probably need to straddle the lanes, a signal on the approach then a signal to leave the roundabout makes perfect sense.
My frequent words of wisdom on this subject are along the lines of " always make sure the signal will mean what you want it to mean to whoever it is who can see it. "
Hope this helps, Pete 