The Celtic Bakers

I’ve come across the Celtic Bakers because they have a stall on Archway Market. Now, I’m always looking forward to Saturdays, when I can buy yet another loaf of delicious bread.
Let me tell you this: I’m a picky German, who’s used to good bread. And good bread for me means bread that isn’t filled with air-​bubbles, is made with flour other than refined white flour and which contains loads of crunchy seeds. (These seeds are very good for your digestion ;-) My test for such a bread is always to weigh a loaf before buying it — if it’s heavy enough (meaning, it’s not too airy, but moist & dense… I will buy it!
Seriously, I don’t get it: why is it so difficult to find this kind of bread anywhere outside the German-​speaking world and Scandinavia?