Scirocco Register

So yesterday I had the shock of my life when I hit the accelerator and the throttle jammed open.
Pretty certain I found the cause, the nut on the larger butterfly (I'm using an audi body) wasn't tight. Consequently when i opened up the power hard the cable would keep pulling opening the larger port way too far.
Or, at least I think that's the problem.
I took up the slack on the go faster cable (and lost the bloody clip in the process) and tightened the nut.
So here's the thing:

Am I on the right path or by tightening the nut have I jammed the larger port shut?

If I drive slowly then everything appears fine and the tick over is where it should be. Hit the pedal however and everything goe a bit mental.

Realise this'd probably be a lot easier with pics but totally forgot a I was far too busy trying not to fill my crackers.

i'm assuming there's nothing stcking up that can foul on the underside of the bonnet? (check for scratch marks)

can you not just pop the pipe off it and get one of your household staff to operate the pedal for you (engine off) while you watch to see everything looks to be moving as it should?

This had been my plan but I was halfway back from the Grange to Hq and most of the staf were away preparing for a spot of Saturday dogging. Going to try and pop up there one night this week but work is currently being an utter parsnip