Out of curiosity, I checked the ingredients on a couple of random loaves in a Tesco today. Both were 'decent' brands (one was a Warburton IIRC) and both had salt at 1%. What strikes me is that I need to add a minimum of 1.25% salt for the dough to rise satisfactorily, so how are the commercial bakers doing it? In fact, commercial bakers use British flour which is low in proteins and gluten and is normally used abroad as a livestock feed. The bread flour we buy (including that which is milled in the UK) is imported from Canada because the quality of British flour is too poor. So not only are commercial bakers making their bread using less salt than is required, they are doing it with flour which is too weak to give a good rise. Oh, and they only prove their bread for 17 minutes.
The more I look into this, the happier I am to bake my own bread.