hi frances i think you may be correct
i found seven john cowleys in lonan in 1841and tried to trace them all through the censuses then i realised my one was born in marown his family was living in lonan
there is john cowley with parents thomas & isabella that appears in 1841
then i find him 1851 in lonan as a servant for the kermeen family
no trace 1861 1871 then in 1881 i think he appears again
john cowley wid age 49 born 1832 marown
quarrier 13 st barnabas square douglas

elizabeth daughter age 20 born 1861 douglas

henry son age 14born 1868 douglas

so he must have been around
i have tried to trace his wife with no luck
then he appears in 1891 living
with the quine family at strand street douglas
listed as father in law presumably the wife mary quine is another daughter born abt 1863
he is mentioned in his fathers will in 1898 so at that point he was still alive (he was left £5)
strangely there are quines also mentioned in the will they are the children of johns sister mary ann
if anyone can shed a light on the missing years i would be grateful