Gesneriads are remarkably easy from seed. Sown directly onto moss in a nice terrarium, I would expect very high germination rates. There is a society in the US with a seed bank. I don't know what is involved in mailing seed from the US to Europe, but packets of dust-like seed easily travel in letter envelopes. Perhaps there is also a European society. Just remember, before ordering too many packets, Gesneriads are remarkably easy from seed....
__________________ May the bridges I've burned light my way.