Ok I've found a pretty good guide on the net (not mine) but here it is, may be helpful to a lot of us!:
SAI, N249 and N112 Removal Part 1
Jack car up and place on axle stands.
Working from underneath Remove bottom engine shield (4 torx screws)
Next unplug SAI sensor
Remove the 3 x 10mm nuts holding SAI to Bracket(note you won’t be able to remove the SAI yet, not enough space) Also you can remove the 2 plastic hoses to the SAI to get better space if needed.
You will need to remove 3 x allen bolts holding bracket to engine. Top bolt pictured is tough to get to. But I found it easier from above engine using a small ext bar onto allen socket and then a knuckle joint and another extension bar to the racket.
The lower 2 bolts not really a problem to get to (pic shows where they were)
Now you can unclips the input and output plastic hoses from the SAI and then remove the SAI from the car.
Both SAI and mounting bracket removed.
Next was to fit the resistors to the wiring loom to fool ECU the removed parts are still there. Pic of what they look like crimped and ready to fit.
Fitted to the wiring loom.
SAI, N249 and N112 Removal Part 1
Jack car up and place on axle stands.
Working from underneath Remove bottom engine shield (4 torx screws)
Next unplug SAI sensor
Remove the 3 x 10mm nuts holding SAI to Bracket(note you won’t be able to remove the SAI yet, not enough space) Also you can remove the 2 plastic hoses to the SAI to get better space if needed.
You will need to remove 3 x allen bolts holding bracket to engine. Top bolt pictured is tough to get to. But I found it easier from above engine using a small ext bar onto allen socket and then a knuckle joint and another extension bar to the racket.
The lower 2 bolts not really a problem to get to (pic shows where they were)
Now you can unclips the input and output plastic hoses from the SAI and then remove the SAI from the car.
Both SAI and mounting bracket removed.
Next was to fit the resistors to the wiring loom to fool ECU the removed parts are still there. Pic of what they look like crimped and ready to fit.
Fitted to the wiring loom.