Do you have a photo? It looks a lot like Devon Green to me from internet photos.

DD

I was looking at this one on the HL auction from Naylor.

They say: "Hosta 'Grunspecht' [M] (Klose) This introduction from Klose of Germany has been around for many years but just recently available. It is a shiny dark green plant from the Tardiana group with very thick leaves...different from H. âÂÂDevon Greenâ as the leaves are thicker, more spade shaped, and slightly wavy"

Margaret

I was looking at that auction too. According to a German hosta dealer, this is a Halcyon sport with glossy green leaves of extraordinary substance. Heart shaped at the leaf base with a lance like tip. (Their words not mine)
Link below is to the dealer's page showing only a potted division.

Here is a link that might be useful: German hosta dealer / Gruenspecht