http://www.the-saleroom.com/en-gb/au...5-a50800e368c4
These types have been a point of contention. There are some of this exact same type that have "Girandoni" + "Penzing" markings that have gone for extremely high auction prices. My suspicion has been that these are more likely of English production with the supposed Austrian version having faked-to-deceive markings. For one thing, while Girandoni certainly lived and produced his guns in Penzing (a suburb of Vienna) it seems very unusual that he would have marked his guns as Penzing rather than Vienna. There have also been examples seen of this identical type with no markings at all; making it a relatively easy proposition to convert a ho-hum collectable into a prized and very valuable historic collectable. As I recall, the Girandoni/Penzing example went for something over 10,000 euro at auction.
In my reference books, I don't see any British gunmaker named Echad. It appears that this is a Hebrew word that means "unity" so perhaps it is the proper name of the original owner.
It would be great if an owner of one of these would take the step of having the wood analyzed to determine the source. Should at least be able to determine if the wood is of English, Austrian or perhaps some other origin.