Thanks for the responses.
Regarding the Magic Roundabout, I lived in Swindon at the time that it was constructed and used it on my daily commute.
I always thought it was fine for locals but murder for strangers.
There was an interesting interlude when they first worked on it. It was originally a single roundabout with a massive central island which they swept away and tarmac'd over and experimented with various options using cones etc. They would then halt all entry points until queues built up, then release them simultaneously to see how it would cope with traffic saturation (the boffins observing from a temporary tower in the middle) - they were exciting times!
Re the Dutch system which Buenchico mentioned, here is another item on it which I came across today now it's operational.
https://uk.news.yahoo.com/roundabout-cambridge-cyclists-first-135426074.html