Did you pass up to the north? Did it ease after the crossing? There can also be considerable bus-stop issues there, between the roundabout and the old railway bridge, also causing further back-up onto the roundabout. I'm not sure that it would be legal, even if it was possible, to overtake a stationary bus there, in either direction, whilst the pennies were being counted out, due to the zig-zag markings from the crossing - in fact, I wonder if the bus-stops, or at least the northbound stop in particular, are even legal?
I tend to avoid the so-called busy times, because it's just not worth the effort any more. My current, on-going correspondence with our paid professionals does not give me any hope for improvement - ever.