Did you know fantastic help is an anagram of Planet Catfish? This forum is for those of you with pictures of your catfish who are looking for help identifying them. There are many here to help and a firm ID is the first step towards keeping your catfish in the best conditions.
It's common for people who don't know what they have to throw a name/number on a fish in hopes they can get more for them than they're worth. It may not be ethical, but does happen. I recently went through a similar situation while trying to get Ancistrus claro. The pic sent was the right fish, but the fish weren't. I do finally have the right species, but from a different seller.
Impossible only means that somebody hasn't done it correctly yet.
L 183 = Ancistrus dolichopterus. At least in Germany (might be similar in England) the common bristlenose (like yours) is most often sold under the wrong name A. dolichopterus. This might explain how it came that it was sold under the wrong name.