Complex sentence: The Beauforts encountered Messerschmitt Bf 109s protecting the battleship and only four returned; shortly after, Beauforts were grounded for modifications to their Taurus engines.
Split into simpler sentences: The Beauforts encountered Messerschmitt Bf 109s protecting the battleship and only four of them returned. Shortly after this the Beauforts were grounded for modifications to their Taurus engines.