Theres 2 bolts by the speed sensor. the one nearest the starter motor (youve removed the starter out the way havent you) Thats the awkward one. just patience and trying and trying will get it, i used a spanner if i remember right, and it kept falling down the back of the engine. i also went in from the engine bay under the plenum.
The other one you need to go in through the driverside wheel arch where the steering rack goes through with 2 or 3 extensions if you dont have a long reach.