Very interesting. Jen and Skoosh.
So we have a John BLAIR, Hotel Keeper in Glasgow in the mid 1820's. Matches the alleged occupation of the father on the Death Certificate for Gordon BLAIR, Australia.
The Gordon BLAIR who married Jane NORVAL in 1850 would probably have a birthdate before 1830, in order to be of usual marrying age, and the sighted one on the 1841 census, aged 15.(reply #8) would confirm this birthdate.
The confusion about place of Birth is a stumbling block.
Sue