He was s of Illtyd Humphry MOSTYN 1907-82 (3xgt gs of Sir Edward MOSTYN 5th Bt 1725-75, 4xgt gs of Sir George BROWNE 3rd Bt c1694-1754, 5xgt gs of 1st Earl of LICHFIELD (of 1674 cr) c1656-1716 and Lady Charlotte FITZROY 1664-1718 d of King CHARLES II) and Joan Athol d 1989 d of Charles J RADWELL. He m 1963 Susan (Suzy) Wallace JOHNSON and had three sons and 6 grandsons (all listed in DPB and mentioned in the death notice).