Common names are so regularly interchanged and abused by fish shops that it would be impossible to ID your plec without a picture. If you can get a photo maybe one of us lot can have a go at IDing him for you
That's a very common/cheap one, but there are literally hundreds of different ples, so it could be one of a few without knowing the scientific name/L number or seeing a photo.
Sorry I can't be of more help - maybe you could have another try at getting a picture so we can help more?
You said "it looks very much like this but with more spots", not that it looked exactly like it. Even so, the link you gave doesn't even say what species it is, it just gives a common name.
I still think you're best off taking a picture of yours, as just looking a bit similar isn't going to ID him - there are tonnes of similar plecs with varying needs.