I think MK probably has more roundabouts but I don't think it can compete with Swindon's "
Magic Roundabout" which is 5 mini roundabouts arranged in a circle to make 1 big roundabout
It particularly confuses people because as you treat each mini roundabout separately, you can go round the big roundabout in either direction
There is a similar one in Hemel Hempstead which I used to have to use on my commute to work which has 6 mini roundabouts - you could spot someone who wasn't used to it from a mile off as they always looked terrified.