The photo may look like the surface of an alien planet, but is in fact the contents of my mushroom tray after two weeks.
Which is annoying, because according to the instructions:
'Mist the surface of the peat to keep moist until tiny white 'pinheads' appear after about a week, then stop spraying water until the mushrooms are about the size of a pea. Once the mushrooms are about 3cm in diameter they are ready to harvest"
It's all going rather more slowly than anticipated, and although there are definite white specks of proto-mushroom visible, they seem to be outnumbered by a more ominous grey mould across the surface.
Although possibly the tub/tray/thing was too high up in the airing cupboard so I've moved it down a bit, closer to the radiator at the bottom. But not right at the bottom, as that's where the cat sleeps, and there's a very real concern she might view it as a new and interesting place to poo.