I agree the car was too close, but the rest of what you say here is an unnecessary and ridiculous assumption, showing a clear and unjustified bias against drivers.
No it isn't, the only reason for the painted circle is to indicate the give way to the right rule applies. The mini-roundabout law clearly states that the roundabout centre can be crossed at will. Indeed, it often has to be.
Me too, I take command of more road space in these situations, but once again you make an unjustified assumption about the driver. You've judged him from his behaviour after he had been wound up by the cyclist, but we've no idea what he is like normally.
The most important thing for all road users to have is tolerance. We shouldn't battle for road space or argue about it in that fashion, we should share the roads and make allowances for each other, including each other's errors. We none of us are perfect.
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