Hello !

Yes, thanks for your review :)

The venue is not just a LUG, as other activities are organized, although currently we focus on activities around the free software theme. We also organize parties, non-profit organization meetings, workshop, etc. For instance, it's also the HQ of a non-profit organization (Neutrinet). That's why I thought that amenity=community_centre would fit here.

The address at 121 is a private house, but Caldarium is in a large greenhouse next to the house. So yes, it's not the same building, but same address. No problem for removing the address on Caldarium node :)