I bought my Brompton new in 2014. It is a 6-speed. As well as I can remember, when I first got it, it shifted from the smaller rear sprocket up to the larger by simply on move of the 2-speed shifter. For the longest time, it requires a conscious second push down to start the shift. I asked the dealer about this and he said that was normal. Over time I have had to increase the tension in the cable by moving the ferule to furthest position from the trigger in the shifter mechanism. My question is, is this normal?