i would not do it like Nick. has pictured unless it is a properly prepared rally car. for a road car, i would get a lhd donor vehicle and cut off all panels around the bulkhead to leave a nice tidy bulkhead panel.

on your car you cut out just inside the bulkhead panel and then trim that right back neatly to where the lhd panel needs to weld to and away you go.

sounds so easy