I spoke to a wool insulation provider on Friday; the company is in Dublin but the plant is in north Wales.
The cost they quoted for 60 square meters at 300mm thickness of insulation, delivered to Stockholm, was about 50% more than I had budgeted. Given the kronor's strength these days, I am very budget conscious, so that's a disappointment.
However, I'm not sure I need the full 300mm because this is quite an efficient insulator. They provided a lot of info about thermal conductivity and 'U values' and other technical matters. I will talk to Stefan about this further, hopefully next week. I will also talk to both Jannes, too.
And there are a number of other types of eco-friendly insulation; the X-House people have used flax as an insulator successfully in the past.