There is often insufficient time or rooom to signal when exiting a mini roundabout, but signals should be considered if they will benefit another road user. Any signal needs carefull consideration, as a bad, or confusing signal is worse than not signaling at all, as others tend to act on a signal. I teach learners to consider whether a signal will benefit another road user, and not, as some teach, to always indicate just in case. This might be ok where visibility is seriously impeded, but where visibility of other road users is good, why, if you can se that no one will benefi?
This junction is one that I use with regularly with learners.https://firstname.lastname@example.org ... a=!3m1!1e3
I teach learners to signal left if there are approaching road users near enough to benefit from it when going ahead to the NE in Beechbank Avenue. This signal is given relitively late, so as to not lead others to think we are pulling in before the roundabout. When going ahead SW no signal is given. Following drivers are not so much of a problem. Asking learners, when safely parked up, what signals they think will benefit others, and whether those signals will cause confusion, does help them to think about signaling and a given situation requires a signal.