What's the correct placement for cast iron fireback?

[Minkeycat]

I'm putting an old fire back into a fireplace that we recently exposed. It's one of the cast iron ones and it must be the heaviest thing I own including my anvil. I also have a pair of iron fire dogs that I'm told are original tudor ones and that I should take good care of. I'm wondering if the fire back should stand ON the back of the fire dogs or should it sit on bricks? I only want to move the fire back once and I want to get it right so that it looks 'proper'. I've attached a photo which I hope shows the issue.
The fire is never going to be lit as the chimney stack above it consists of solid concrete thanks to a vandal in the 60s. And it's roofed over. With thatch!

As ever, any useful suggestions appreciated. Cheers.

 

[Bogart]

Have you got a grate to go with it?

 

[Minkeycat]

No. Unfortunately that's currently lost but there used to be an iron "basket" that used to be suspended between the two dogs.

 

[Edward Ian]

Since the purpose of the fireback is to protect the brick at the back of the chimney, I think that the correct answer is that it should stand on the floor.

 

[Kearn]

On the floor at the rear of the hearth, vertically, not leaning at an angle and it will need to be attached to the rear wall of the fireplace to secure it.