We bought ours from an outfit in Estonia, as the baltic states are very experienced log structure builders, and the baltic pine forests give a good and consistent quality of wood. I looked at portuguese suppliers but the offerings were much more "shed" than cabin, and the thickest "logs" I could find here were 35mm - not so much a log as a plank. Our freight cost down from Estonia was about €4k - full lorry.

Ours is 70mm milled logs, fit together like tongue and groove. Generally really pleased with how it's come together, although I need to finish the roof, which got postponed by weeks of rain.

Only thing I'd say is that they can be tricky to get permission for in Portugal, but it really depends where you are. Where we are, in the north, where the fires aren't so bad, pretty much anything goes - I have a signed note from the local council saying "it's your land, you build what you like".

Only other thing is don't underestimate the labour. I naievly thought we'd have it up within a few weeks of the kit arriving, but it's been more like four months, and we're still not quite done. Oh, and don't build in winter :)