I went in the corner off top of wing and bonnet.
Piece of tumble dryer ducting going from airbox, though hole in inner wing, run horrizontally between inner and outer wing, just being supported by cable ties.
Outer wing comes off with about 4 bolts
Straight piece of drainpipe from B*Q running up window, 45* bend, and a drainpipe bottom on the end (the bit whih goes at the bottom of a drainpipe, directing water into drain - downpipe shoe??). Glue together with plastic cement (marley solvent or something i used)
Line up the pipe along the windscreen BEFORE marking and cutting the hole.
Cut hole in wing, smooth off cut and then i slit the outer sheath of a bit of cable and put around edge of hole to neaten it up.
Put bendy pipe over drain pipe, filled gap with bathroom sealant
and the did up jubilee clips. I riveted a bit of the jubilee lip to the wing to hold the bottom part in place (its hidden well). Attached the top to my light bar with cable ties.
Put wing back on
Thats about it.
Oh and to finish it off i got one of the square covers which go over the drain which the rain water goes into from the downpipe which have the circular pattern, And trimed it so it would fit into the top perfectly giving a nice gaurd