Didn't leave me with no toilet over night though.
After breaking up the old one to throw away they explained that it's exit-pipe had almost blocked up with limescale, so that's why the flush has been terrible for ages.
I have now christened this toilet and can confirm that not only does the water inflow seem more powerful, it also drains without having to poke at it with a brush.
They've agreed it should be black tiles at the shower base and seem to have a plan for that and tiling the sink area tomorrow.