Anyone any ideas how to remove one of these preferably without destroying it?

https://www.dropbox.com/s/bs9oxykyve...20.12.jpg?dl=0

Others I have seen usually have two brass plated mirror plates either side which are sometimes sunk into the plaster with filler on top to disguise them. I have run a magnet down the edges and have not picked up the presence of either plates or screws unless they are actually brass. Whatever is holding it in place is pretty solid with absolutely no give anywhere.

I need to get to a pipe that is running under the bit on the floor. It will be replaced eventually so if I have to wrench it off I will do it but would like to replace the surround temporarily if only to cover up the hearth behind it until I am ready to replace it.

Richard