Complex sentence: The British had already supplied, among other goods, 40 million 7.92 rounds the previous month, but had not yet fulfilled the Greeks' mid-January request of 300,000 uniforms and sets of shoes.
Split into simpler sentences: The British had already supplied, among other goods, 40 million 7.92 rounds the previous month. They had not fulfilled the Greeks' mid-January request of 300,000 uniforms and sets of shoes.