Republique still claims to. Petit Trois offers something it refers to as “Brittany Sole” but it is unclear if that is chauvinism or a distinct species. It also used to be on Cut’s menu (and was deboned table side) but no longer.
I bought absolutely fresh (not frozen) Dover Sole at the Fish counter at Eataly. I saw Grant, the manager, unpack it. He cleaned the whole fish for me. We cooked it on the bone. It was as delicious as any sole I have had in Europe. Call and ask for Grant, the manager of the fish market. He’ll tell you if they have it or when they will get it. It was $30 a pound. One fish was about 1 pound and enough for 2 people
All that is true. But naming conventions for fish causes a lot of confusion.
It is extremely unlikely that you bought “true” Dover Sole.
Fishmongers and restaurants are legally allowed to call a completely different Pacific species Dover Sole.
Many people think the fresh Pacific Dover Sole is actually better than the frozen true Dover Sole that is available here. I wouldn’t say you got an inferior product AT ALL. Just saying that if someone is looking for true Dover Sole specifically, it’s actually a challenge.
I may not have all relevant information, but that is my current understanding.
Might be one of those things that restaurants can special-order that aren’t generally available retail, like scallops with roe or real langoustines. The Eataly fish counter might be using the same specialty wholesaler, or they might have connections through their European branches. Sometimes those wholesalers will sell retail
Have also had true Dover Sole at Water Grill, but only at South Coast Plaza. Never go to DTLA anymore. That and the fries are just about the only things worth ordering there. Maybe a couple of oysters too.