I think the issue is less about phasing and more about vehicles entering the junction when it's not clear to exit on the other side and then remaining there when the lights change, preventing traffic from other directions moving, thus causing a jam. Yellow hatching at the junction would encourage more discipline as those tend to be more observed by more people.

Cars parking on Dartmouth Road, narrowing it, worsens the issue.

The cause is poor driving. The solution is enforcement of the Road Traffic Act.