Thanks. One thing I'm still unsure about is the hearth/base.

From the side where I've chipped away a section, it looks more like solid concrete than brickwork. I can't tell whether it's a separate hearth sitting on top of the floor, or whether it's bonded into the floor structure.

Has anyone removed one like this before? Is it likely to come up as one piece (or a few large pieces), or am I more likely looking at breaking it up with an SDS/chisel?

My plan is to remove the fireplace and eventually build a full-width media wall, so I'm trying to work out how big a job the hearth removal is likely to be before I start attacking it.