John Carnegie Allan, 1849

[lyndyloo6]

Hi There,

The above person is my 2 x gt grandfather.  I have been researching him for several months.  He was born on 5/11/1849 to parents William and Catherine Allan, ms Carnegie.  Born in St Clements Aberdeen.  He married Helen Wemyss in 1877.  Helen was from Bervie and lived in David Street. 
John was not listed in the 1881 census with his family and his wife is listed as a widow.  He was a ships carpenter.  However, when I was on An.....y last night, it flashed up a match for a John Allan, born in Aberdeen, on board the ship Diana, docked in London on the night of the census.  He is listed as married.  How can I prove or disprove that the John in London could be my gt gt grandfather.  I have hunted all over for a death cert to no avail.

Any ideas or hints would be great

Many thanks,

Lynda