I holidayed in North Devon this year and not too far from where we stayed was this really cool shop. http://www.griffinsyard.co.uk
They described themselves as an organic and natural foods emporium. All I can say, is I wish I lived nearby! They sold unpackaged ‘proper’ bread. They had glass jars of spices, herbs and other dry goods like lentils and great canisters of tea- all of which could be weighed out to your requirements.
Most exciting of all, in their freezer section were these frozen vegetables- packaged in cardboard boxes and made by a Cooperative. You can read more about them here: http://www.natural-cool.com/Natural-Cool.37+M52087573ab0.0.html although it does look like they would have to be flown in from Germany. (I should add that this is my assumption and they may have suppliers based in the UK, or other countries. I personally didn’t get to taste them, as we were only on holiday for a week and would never have gotten through a box!
Have you found sustainable frozen options where you are?