Loads of rockwool under the floor and those bricks are a sort of set of dwarf walls to support the floor better. The old wood is now stinking of creosote to prevent any further rotting. The pipes are from the CH.
The old floor underneath is mostly just rubble - and it can bloody well stay there!
In the wall between the downstairs bathroom and the old kitchen, I have found an old sash window!
The rockwool in the ceiling goes in, together with ordinary outside lights that have energy-saving bulbs in them. These will be recessed into the plasterboard and get a plastic surround when I am finished.
The ceiling is up and the rockwool in in the walls. PU Cellotex boards and a second framework of battens go over that.
Progress is being slowed down, as I also am doing the shed at the same time and I have just completed recording a choir and also wrote and laid-out a thirteen page paper on the theory of time-division multiplexing for ultra-high definition video displays. With the weather being so good, I am concentrating on the shed right now.