Victorian floor - half concrete, half wood / gloss paint

[monkey writer]

Hello, our new victorian terrace house has a rather odd kitchen floor. We ripped up the vinyl and under that a layer of hardboard to discover this: by the external wall there is a concrete section covered in tiles (which have been covered in a concrete leveling scree) and the rest of the floor is wooden joists covered in plywood.

The concrete/tiles and joists are original to the property, though the joists used to have floorboards over them. The properties either sides of us have this arrangement.

There is no ventilation as the ground level outside is level with the inside. There is no physical damp proofing, but there doesn't seem to be much of a damp issue (we're near the top of a hill). Any rotting to the floor was was caused by a leak from the sink, and damp in the walls was, I suspect, caused by woodchip wallpaper and, under that several thick layers of gloss paint.

What would you recommend I did with the floor? Should I take up the concrete section?

Also, would you recommend trying to take off the gloss paint? All over the room or just on the external wall? It'd be a hell of a job as the whole room has it, in places mixed up with or covered with various filler jobs.

Thanks!