Cycling Techniques

My first impression when I saw Eds pic is that it looked unnecessarily disruptive. I dont think riding in an assertive position necessarily equates to not allowing people past.

Absolutely true (the second bit); I was just on the phone to Festus talking about this thread and trainees who find primary position such a liberating revelation that you have to remind them that riding in the middle of a narrow side street with parked cars on both sides does not mean they have to ride in the middle of every road from now on. As SkyDancer says, you adapt to the circumstances. I think Ed's pic is of the bus lane near Clapham Common - anyway it's the same - and it's an odd one because the Super Highway bit makes the bus lane far too narrow for a bus and any rider sticking to the cycle lane is going to be dangerously squeezed out if they do not discourage busses from overtaking too close. But as MF and Multi have said, there is nothing wrong in letting a bus pass if you can do that safely.