I went back to the same shop today, when I bought him there were two other plecs in the tank. They were marked as L66, but this one is very different. After looking at many L66 photos and the article of L66 Vs L333, I am sure this is L66.
I notice on the tank next to it that they had a sign that said L174 on it but and empty tank, could it possibly have been in the wrong tank when I bought it? After looking at some other L174 it is the closest I have seen so far. What do you think?