You dont need to take the bumper off!!!! Its a right b*****d to take off anyway!!!!
What you need to do is stick your head under the front of the car, here you will see 2 or 3 bolts holding a Black pastic sheet (extending off the front bumper) Undo these, and pull the plastic sheet down towards the floor, you can now slide the mesh in (youll have to trail and error it for fit)
Thats how i did it anyway, The front bumper is a right sod to take off