What is your access like? Clearing the debris and bringing new stuff in is what you need to plan for. In my old house I had to bring two tonnes of sand, paving slabs and bricks through the front door, hall/kitchen and lounge to get to the garden. Luckily it was dry when I did it.
Good idea. Pretty sure it's on some concrete, but I reckon I might be able to hammer the edge of it or something to try to understand what's going on.
Thanks