suspect Wm is s/o Wm Waterson + Margt Killey (at marriage both of Castletown) (Margt is d/o Wm Killey (tailor, Castletown) + Margt Quayle (can trace via land records)
Margt Waterson d 1819 - will names ch inc Wm who got only 20s but had been prior had been sold some land wch he + wife Ann sold in 1834 (tho he had already mortgaged it)