The grille is held by the two bolts visible on the bottom trim. Remove them and the grille slides down and out.
If you have a number plate box, you must first remove the number plate and box.
Beware that when refitting it's easy to chip the paint on the bottom corners of the wings because the fit is loose.
Earlier cars had rivnuts on the lower panel, but you may just find oval holes.
While I was inside the cowl, I added a carbon fibre panel on the bottom, and neoprene covers on each side to duct air through the rad instead of round the edges.
