Here's a bunch of stuff from the T-shirts page on Etsy, shipping to the UK. No shipping options for anything as far as I could see. Giant Bomb seems generally more expensive than anything else, but not extortionately so.
The irony is that roguelike is probably the most meticulously defined genre of them all. Though, while ridiculous as that Berlin interpretation nonsense is, I do find it pretty dumb when people describe games as roguelike just because they're hard and you die a lot. Dark Souls is not a roguelike. It just isn't.