The new kitchen won't occupy the entire space available: an area will be separated off with a plasterboard wall to form a small utility room that will house the water heater, the washing machine, a toilet and hand-basin. Before the concrete goes down, we just need to re-position the soil pipe to take the toilet in its new position. Cut the old pipe, then glue the new one in, testing different angle joints and pipe lengths to get the connection in the right place (we hope). A bit of a race against the concrete tide, but done in good time.
Eventually, the floor is covered. (The blue pipe you can see hanging from the wall is the temporary feed of cold water to the old kitchen to keep it going during the upheaval.)