We opened up five chimney breasts that had been sealed in and put four fireplaces (and the oven) in them. One of the replacements was a salvage. After having a lot of trouble getting another salvage to fit we replaced the other three with cast iron replicas. It was easier to get the right size and the whole house was a disaster so we just wanted to finish it!
I used to have a back boiler and an ugly gas fire on the front, I bought a fireplace from someone on eBay and my plumber installed it for me - I have uploaded a picture of how it looks now (although the picture is a bit dark!).
There is a post from a few years ago where people uploaded pictures of their original fireplaces - I have just posted a reply on it so it should appear at the top of the feed