So I couldn't to this particular sensor from the bottom of the car, since it was too tight. but when i was replacing throttle body i noticed that there's a massive gap where you could actually remove the sensor and replace it there and then.

you need to get both hands (one down the main hole where the throttle body is removed, the other past the valve cover) in there to unclip it from the harness but once that was done the job was a breeze.

hopefully it makes someone elses life easier.