Thanks all!

Jens wrote: Do you keep them in a cooler room of the house?

They are by a south facing triple-glazed patio door, so it doesn't get too hot and there is nice air flow in the summer.

Hello all, I'm Len and I recently signed up here after being shown this board by Waxsimulacra08 8) I've been growing cacti for a few years now, and the addiction has only increased. They should come with warning tags! My favourite species include aztekium, lophophora, sulcorebutia (rauschii mostly) ...

That would be a Pilocereus azureus, or a Pilosocereus pachycladus if you swing that way.