First thing was to fit the manifold into position using the stock ford gasket and bolts sourced from GBS (Note the stock OEM bolts are too long for the GBS manifold). Simple job end result thus:
now that was in position I could start taking some measurements and datums for where the exhaust exits the bonnet relative to the chassis. I used a piece of paper to mark and make a template which in turn I transposed that onto the side of the bonnet. 
Clearly marked it was a case of taking a drill bit and drilling alot of holes around the perimeter of the the cutting and then using a junior hacksaw blade sawing through each hole to cut out the unwanted piece of metal.
Once removed it was a case of taking a metal file and cleaning up the outline and making a nice smooth finish. Apply some edging strip and one aperture cut int he bonnet to provide an exit for the exhaust manifold.
NB - the eagle eyed readers among you will note the bonnet has suddenly been wrapped in this sequence of photos! I adopted the carbon fibre look for the bonnet and when doing it forgot to take the photos, so only the finished article to note in the pictures.
