Complex sentence: More than 500 Merchant and Royal Navy sailors and airmen were killed and only five of the 14 merchant ships reached Grand Harbour and the siege continued until the Allied reconquest of Egypt and Libya.
Split into simpler sentences: More than 500 Merchant and Royal Navy sailors and airmen were killed and only five of the 14 merchant ships reached Grand Harbour. The arrival of the remains of the convoy did not break the siege, which continued until the Allied reconquest of Egypt and Libya.