That's probably it. Chain was rubbing on the outside of the FD cage when on the big ring. Trimming sorts it, but now I have to double click every time I move between chain rings...
So my next question is, how do I re-align a front mech?
Take tension off the front cable, you may be able to do this by selecting the small ring then going for a 'trim click' if there is one or failing that back off the cable adjuster or the cable clamp.
Have a good look at how high the front mech is
before loosening the bolt or clamp that retains the mech and then turn it so that the arms are parallel to the rings then tighten the bolt back up now check that the mech is
at the same height as before then re-adjust the cable to where it was before.
The bold bits are the most important, the mech needs to sit at a certain height above the chainrings, there is a bit of tolerance (couple of mm) but outside of that it won't work properly so the trick is to turn it without changing the height hence taking the cable tension off so that it's not pulled lower down the seat tube.
