Me again... I think I have a definitive answer, They were 1C1R says my programme
Mary was actually a Murly her father (edward junior)'s father Edward having dropped the e two generations earlier. His father Thomas b 1713 speled it with an e and the eldest son, Thomas b 1738, held on to the e which he passed to his sons John, Thomas and William (as you said later Capt. RN retd.