My 4xgt grandparents were JOHN and SARAH LEWER. I have settlement documents for them dated 26th April 1793 when they were granted settlement in the parish of St Thomas in the Cliffe, Lewes from the parish of Billingshurst. John was a lath maker and at that time they had four children: SARAH aged 13 "or thereabouts", JOHN aged 11 "or thereabouts", Maria Ann aged 8 "or thereabouts" and Samuel aged 2 "or thereabouts". The family appears to have remained in Lewes from 1793. Two more children were born in the town, ANN GORING on 23 July 1793 and my 3x gt grandmother EVE ANN in 1798. According to the Sussex Burial Index SARAH LEWER was buried in Lewes in 1799 but I have no other details. This burial certainly wasn't the daughter Sarah as she married in 1803.
I also have an extract from the Diary of Thomas Turner who was a parish official in East Hoathley. He describes conducting an inquest in Nov 1764 into the death of MATTHEW LEWER a lath cleaver who was found dead in woodland after a day working with his nephew Matthew and John, the son of his nephew. I think this John may well be my John, given his occupation as an adult.
I have had difficulty finding anything concrete about John and Sarah and have seen a burial record for JOHN LEWER at Bury in 1826. I did wonder if he was mine but having seen your posts, am pretty sure he isn't. I think you are right in saying there were two families headed by John and Sarah Lewer in Sussex at the same time. I think my couple are the ones who married at Buxted in 1779. However, many years ago I recall seeing a record somewhere on the internet which connected a John Lewer with a Sarah Goring - I'm not sure what it was now. Since my pair's next to youngest daughter was Ann Goring Lewer, I do wonder if there is a something to be explored there. I wish I could since I have never been able to find the record again!