Complex sentence: Most German troops encountered were so stunned by the bombardment that they were incapable of resistance and surrendered immediately, despite few of the concrete pill-boxes and Mebu shelters being destroyed by the British artillery.
Split into simpler sentences: Most German troops encountered were so stunned by the bombardment that they were incapable of resistance. Many Germans surrendered immediately, despite few of the concrete pill-boxes and Mebu shelters being destroyed by the British artillery.