Lovely! And good to know. I have seen "bellend" used a fair bit online lately, mostly in hostile comments under Youtube videos where various people who seem to meet your definition of "cock", "bellend", and "knobhead" go on insulting each other viciously for 20 or 30 posts each over something trivial they've got their knickers in a knot about.

I particularly like "bellend". It has a marvelous sound to it, though I'm not sure what it is supposed to refer to. Anything to do with doorbells?