[mowflow]

Yellow box means don't enter unless you can clear it and the other junction is a give way. I say you are in the right as the traffic in front of you was free flowing into the roundabout so you were going to clear the yellow box. Regardless of how fast you were progressing the other car is at a give way and therefore you have right of way. End of.

On the other hand. It looks like you hesitated a bit and sounds like you made eye contact with the other driver. They still shouldn't have assumed though. Plus their car is much smaller than yours so you are right.