sorry re marriage I misread my records - indeed 1844!

the 1851 census gives Margt's birth parish as Maughold - whichich fits Hugh's dau - however there appear to be several john cowins s/o thos + margt's around at that time!

at Ballagawne in 1841 along with Thomas + margt were John Cowin age 25 (?son) + Margt Gill age 9; Margt is almost certainly the d/o John Gell/Killy + margt Cowin - this margt cowin was born lonan 1812 (from 1851c) but there are two contenders though I suspect wm cowin + isabella stole as parents (thus visiting niece?)