Complex sentence: That attack was postponed until the 14 June but PLAN withdrew on 12 June with the SADF stopper groups failing to prevent the withdraw and by the time Battle Group 10 arrived it was deserted.
Split into simpler sentences: That attack was postponed until the14th of June, but PLAN withdrew on 12 June, with the SADF stopper groups failing to prevent the withdrawal. Consequently, by the time Battle Group 10 arrived, it was deserted.