Hi Charles,
I concur. Our family experience was in the Outer hebridies where potatoes were planted inside piles of seaweed. Very no-dig. I recently had a conversation with my mother about this practice and apparently it dates back to before the days of The Potato Famine. Source is oral history I’m afraid.
I guess you cannot call the Gaelic lazy beds no-dig, but the turfs were important in our part of the world to hold everything down and not get blown away! (context is everything!)..
Richard, you will be astonished at how quickly seaweed rots down, but be warned, dont let it rot before you use it as it can lose its goodness quickly.
BR
Neil