Okay ... so ya wanted to take apart the complicated stuff ... couple probs:
1) I don't have my camera to hand right now (it's across the province at the moment);
2) I'm not going to strip out all those tiny little springs if I can't even get a good photo.
So I'll try this and see if it helps. Again, sorry for the picture quality.
These pictures show the knocker already in place. They're intended as a bt of a guide to show you how it goes in and where the three springs that attach to it go.
At the top of the sear, which is the other silver bit above the knocker, there are two springs; one on the left, and one on the right (the sear spring and the knocker spring; parts 31 and 34):
RightRearChassis.bmp
RearChassisInternals.bmp
This is the third spring, the knocker return spring (part 32):
LeftRearChassis.bmp
And this is the whole thing with the right rear chassis cover put back on (takes a little poking of springs with a toothpick or something similar to get it to click into place, in my experience):
RearChassis.bmp
I hope that this helps somewhat. I can't get any clearer photos without an actual camera, unfortunately; sorry.
I hope that you can get the rear chassis back into the frame form this point (it just drops in, with two pins that hold it in place).
Let me know if I can be of any more help.