Hi all - a little urgent help please if possible?

Trying to install H&R lowering springs into the rear of my i8 (fronts done) and we're stuck, unable to remove the three screw bolts from the top hat (item 2 in the image). They're very small and super tight, and we're on the verge of snapping them, and can't use any heat etc as they go into carbon fiber.

Has anybody done this before? Could you please help? Perhaps you can put me in touch with your workshop who did it? Car is stuck on the hoist in the workshop now, so it's pretty urgent I sort this out asap, otherwise the fronts will have to be put back to stock, I'll have to pay for a lot of unnecessary labour time, and I'll also likely cry myself to sleep.