No it hasn't, 'technically' or otherwise.
So on a multi-lane carriageway with vehicles in all lanes, my speed and position in lane 1 is dictated by the slowest vehicle in any of the lanes to my right?
I think you're misunderstanding the HC.
Rule 268
Do not overtake on the left or move to a lane on your left to overtake. In congested conditions, where adjacent lanes of traffic are moving at similar speeds, traffic in left-hand lanes may sometimes be moving faster than traffic to the right. In these conditions you may keep up with the traffic in your lane even if this means passing traffic in the lane to your right.