The junction at the crest of the hill is controlled by traffic lights and there are often long queues in the right turn lane. The left lane however is rarely used.
Would anyone use the left lane if there was a slow moving vehicle at the head of the queue at the light; use it in order to turn right. The example I am thinking of involved a traction engine at the head of the queue.
I think I am confused
how could you use the left lane there to turn right as it is physically filtered off to the left - if there is traffic queuing on the right you wouldn't be able to get in there... If as ancient suggests you are thinking filter left and then do a u-turn / go through the forecourt and come back again - totally legal, though it seems a hassle just to jump a queue
today on the roundabout Junc. 15 of the M4 - over the M4 and heading NNWish on the A419 there are two lanes at the traffic lights going straight on into the two lanes of the A419 and one filtering right to the M4 East bound - there was a small lorry in front of me in lane 2, a car came up in lane 3 and when the lights went green out-accelerated the lorry and drove down the A419 - did it smoothly and cleanly - technically not the correct lane, but actually a good skilled move. He didn't avoid much traffic as he had been between me and the lorry - still not sure why the lorry was in that lane!