OK, Fluff, the spring you have in mind came about because of the lockwork changes in the gun in the 1940s when the new hammer block was adopted. The hand is not controlled by a spring in the trigger assembly as it is now.
I forgot to charge the batteries in my camera, so I don't have any illustrations right now. Hopefully I'll be able to get a partial charge and post some pix.
Longbow, essentially I believe your hammer block mechanism is not functioning.
When you remove the sideplate and look at it, you'll see the slot in the plate in which the hammer block is recessed.
Holding that part in place is a cross pin that is just above the hammer pivot pin hole.
This cross pin is spring loaded, and bears on the hand. At rest, the pin is supposed to protrude into a recess in the hand and allow the hammer block to come between the hammer and frame.
As the hammer is cocked, the hand moves up and cams the pin backwards. This, in turn, depresses the hammer block so that the hammer can fall fully.
This spring loaded pin, when fully functional, serves also to keep the hand pushed forward.
I believe in your case the hammer block pin is crusted into the frame probably will old grease and dirt. That's what the British found in their guns during WW I.
If the pin is back, which I suspect that it is, this allows the hand to drop out of proper alignment when you elevate the muzzle.
You need to soak the sideplate and get that pin operating properly.
Since it's not operational, this means that the hammer block safety has also likely been defeated.
I'm trying to figure out how to get this pin out of the frame, but nothing I'm trying is working.
But, in any event, this pin is the root of your problems. I'm certain of it.
I'll take some photographs as soon as the camera batteries charge.