I checked the 1851 census, John, son of John And Jane is now 35, living with his parents in Surby and unmarried. He is a farmer's son.
The 1841 Rushen census has only two other John Sansburys. One is 27 and the other 12. The 27 year old appears to be the son of Richard Sansbury and Margaret Gawne. In 1851 he is a mariner, aged 40, married to Ann aged 30, with 4 children, William, Edward, Jane & Margaret.