The 'not using the cycle path' has raised my hackles a bit!
You do understand that theres no requirement to do so, and in plenty of cases its inappropriate?
Riding a road bike at 30+ kph is not appropriate for shared use cycle paths, and the road is the right place.
Also, dear old Aberdeen and shire cooncils do not treat the cycle paths, which are dangerously icy in winter.
Filtering through slow moving or stationary traffic, eg at the approach to junctions or roundabouts is fine, so long as you don't filter up the inside of traffic turning left and put yourself in danger.
Can you elaborate on exactly what roundabout this was, and what direction you were approaching from?
I ride in the Westhill Kingswells road and over the Kingswells rab every day, and yes, I get shouted at by usually one person each day.
F.