Thanks all.

Thanks Wiebe.

Grown from a pack of seeds marked simply "Lobivia", can someone put a name to this for me please? It is in a 3" pot. The flowers are quite pale, not quite as bright as the photo has come out.

I think that if we were able to put temperature sensors at every point in the greenhouse it might be revealing. I've only ever had scorched plants on the south-facing side next to the glass before automatic vents and I suspect that in some spots the heat can get way hotter than even the natural habi...

It looks like it is doing quite well Not a cactus though- it is a Euphorbia (trigona?). I don't know much about Euphorbias so someone else can maybe confirm. African plant, and I think tolerant of a wide range of conditions.

It's a Pilosocereus- probably pachycladus (azureus).

Or a geiger counter...

Looks like Rebutia minuscula var. grandiflora.

Mix it all up thoroughly Chris, not layers. Avoid using multi-purpose compost or the stuff sold for cacti- it usually has too much peat or coir which can attract sciarid flies. There are lots of different recipes (everyone has their preference) but the main thing is that it should dry out quickly af...

Could it be F. wislizeni?
Well done for rescuing it, it looks a nice size.