Complex sentence: The Seacat missile system was fitted to HMS Lincoln in a long refit from 1966--68 and in HMS Salisbury 1967-70 it was the same GWS 20 Optical guided system being refitted at the time to the Rothesay class frigates.
Split into simpler sentences: The Seacat missile system was fitted to HMS Lincoln in a long refit from 1966--68 and in HMS Salisbury from 1967-70. It was the same GWS 20 optically guided system being refitted at the time to the Rothesay class frigates.