Hi Holger – I have just checked the discussion forum for the first time in a number of months. Coal Products in the UK (https://www.coalproducts.co.uk/product/ecoal50) supplies a coal which is 50% bio-coal.
You may be able to order a bag from them.
When we get a supply from the US, we may be able to provide a small quantity. I cannot provide a timescale because Covid 19 has put everything on hold.