Hiya Marius,
My home is not well insulated and so 10C is easily reached and in fact during very cold weather it can drop to 8C in my bedroom!
I have obtained New Zealand moss online from Grobraschener orchideen, Germany. It is expensive!
Over many years, I have compared growing orchids in bark and coir husk chips. If you use good quality “orchid grade” coir it is coir that is actually superior to bark! (I think Roger was using poor quality coir which I have also had problems with) Also the quality of bark can vary sometimes it can be poor too!
I imagine potting media will be discussed in detail at the Feb meeting as it relevant to the topic of the night (repotting). Perhaps bring a sample of your coir to the meeting? See you then and I shall have those free plants for you!