Thanks Picotee and Ray,
I had thought the name was formosana then saw it as formosa somewhere and thought I had got it wrong. Hmm... I've checked the tag and that's formosana (written by the seller). No idea now where I got the formosa name from. I'll change the thread title, thanks for the correction
I take these out the medium each autum and repot each spring, otherwise they would get higher in the medium as the new ones always form higher on the surface, even with standard medium.