Any tips for stopping a creaky ferrule? Its on the headtube for internal routing. Makes a hell of a noise. Tried flushing out with wd40, didnt help. Anything else? Ideally i want to leave the mech / tension alone as it shifts perfect at the moment

They get grit trapped under them and make that noise. Slacken the cable without adjusting the mech by shifting to the biggest cog, then stopping the wheel and shifting all the way down with the wheel stationary*. Pop the ferrule out, clean it all then maybe try a smear of grease to keep it quiet.

*worth doing this every time you clean the bike.

edit dp

Magic, that sounds like it would do the trick without messing up the shifting. Will try in the morning!