Hi John and Welcome.
I am battling with a Series 3 E Type bonnet as well, the centre hump had to be moved 25mm, and I don't how they done it like that, They are huge and I'm in the same boat as Shipping and the actual part is killer expensive.
But there is a company in the States that makes them and many other rust sections.
http://www.monocoque-metalworks.com/main/
Goodluck with your project and post some piccy's up, as we all love piccy's
Cheers John