Dianer,
I too have been looking for John Tennant for years, been through every register and graveyard in the Aysgarth area and found nothing, I have suspected for a while now that is the one on the IGI born in Conistone in 1798, take a look in St Mary's church in Conistone, there are several plaques relating to the Tennant family on the walls, also Burke's landed gentry has a fairly comprehensive family tree for the Tennants of Chapel House dating back to 1572, but it will take a bit of work to see where we fit in, my Nana had a story passed down through the family that there was a couple who married against their parents wishes and they were left penniless, I wonder if it was them - him being a gardener - if you find anything else, please post another reply.
Their Children were : Sarah (1825), John (1829), Elizabeth (1833), Martha (1836), Mary (1840), Robert (1841), Mary & Matthew (1842), Robert (1844), William (1845), Mercy (1847), - Martha is my GG Grandmother
Many thanks, Mary