We've a solid selection of North Sea.
I've owned the Submariner sweater for just about a year now, and it's a great piece. In regards to sizing up, down, etc, although i've never tried a 36 (what i'd consider my true size) I liked the relaxed fit of the 38. The shoulder seams sit a bit low, but I like to think it's part of the charm of a sweater like this.
going tts would certainly work, but it would lose it's appeal.