Hi, My 6 speed Brompton is having a lot of trouble downshifting in the left-hand gear. The sturmey archer hub is working fine, but the chain isn't going from the small sprocket to the large sprocket when I shift using the left hand gear lever. It has no problem moving from the large sprocket to the small sprocket (upshifting). I've followed Brompton's technical guide for 2 speed gear adjustment. I've checked the max/min position of the chain pusher (its fine), then the guide moves on to adjusting the gear cable tension at the shifter end, but its using the old style shifters, and I have the new style. I've tried this afternoon to adjust the tension at the shifter but I can't figure out how to do it! Can anyone help me out?