The hardcore has been laid in the extension and the builders have moved on to the roof. The tiles are coming off - there are a hell of alot of them - and once they've been removed, the chimneys will be taken down. It's all still going very well.
The blockwork wall has been stopped pretty much at floor level - our understanding is that it is of a suitable height for the floor slad to be poured when the southern (gable) wall is removed. Once the slab is poured, the extension is then joined to the existing house and the wals can continue to be built up.
In other news, the builders can't find where the water main is routed - perhaps because it's under the hedge at the edge of the property. The good news appears to be that the pipe that they originally found is an old mains pipe and the actual active mains pipe is a modern plastic 32mm pipe. No one's sure where it goes to, but the pressure is reasonable and it's made of the right material, conventional thinking dictates that if it 'ain't broke ...