The fire pot lifts straight up and you can take it right out of the loading doors easily. Take the bricks out and then lift out the fire pot. Be sweet to me and perhaps I can send off my fire pot to be copied for you.
There are supposed to be three fire bricks over the fire pot around the back of the stove and a large half round brick that makes a baffle to deflect the exhaust toward the upper front of the stove, sort of like a throat in a fire place. So there are 4 bricks total. The three bricks that go on the back of the stove are formed in a upside down semi circle to fit the deflector brick.
I don't think you are going to find replacements for those, but; don't despair. You can form a replacement very simply with the plastic refractory material. Is it called Norexam or something very close to that.
Perhaps someone can give us the correct name. It's what Emery at the Antique Stove Hospital uses.
Perhaps also I can take some pictures of the bricks in my stove and give you the measurements. It might take a few days as I am away from home 16 hours a day at present at work.