So, i6 came back to me - BOTH the bell crank and the flap are machined from the same billet of ally before being coated black, so that's good to know
Decided to remove my DISA yesterday to inspect it. In order to improve access, I removed the pipe from the MAF to the throttle body, and saw this;
Now I had been getting the occasional "lean" error stored along with an oxy sensor out of range, both of which are classic signs of a failed/failing DISA according to Google, however I can see this causing the same, along with an uneven idle?
Removed the boot, and it was shot in several places;
I was going to attempt a repair, but a quick call to Williams, and the part was (surprisingly) only £21+vat trade, so I ordered it to be dropped off today at my neighbour's place in Liverpool and he'll bring it home for me, saving me the trip.
Proceeded to remove the DISA valve, and it's in perfect condition, no play in the flap to crank (ooeerr!) joint and the vac side is fine
Mike