hi
er why would you change the hinges. No body work to remove, bit of an ar*e to get the clips off the pivots (follow the hinge around with your hand, you'll feel the clip (like the one that holds the rear seats in) remove the clip, support the bonnet with a mate, undo the 2x bolt on each hinge, remove bonnet, remove hinges, (que famous Haynes quote) re-fit in reverse order.
Hope this helps
kraM