My 3xgt grandfather Robert Edward Craine married Eliza Frances Despard as his second wife sometime between 1857 and 1864 but as she was Irish I had trouble finding the exact marraige date. In April 2001 I emailed Brian Lawson to see if he could check the 1851 census for a Despard family I had found on my LDA fiches. Brian returned the following -
1851 Ramsey, district2, entry 71, College St
Philip R A despard, head, married, 45, annuitant, Ireland
Ann, wife, married,30, Ireland
Philip R, son 13, America
Francis S, son, 10, Ireland
Loiusa, daughter, 7, Lezayre
Letitia, daughter, 5, Lezayre
Ann, daughter, 2, Lezayre

I, immediately thought this could not be mine as there was no Eliza frances and, with her birth being around 1831, this could not be the right mother. The American birth was also a problem. However I did keep the email.
Recently I found Robert Edward and Eliza Frances' marriage in Liverpool in 1864. her father was Philip R A Despard, gentleman.
Now searching for Philip, I linked up with a descendent in America who gave me the following -
Arrival at the Port of Philadelphia, 7 June 1832
from London aboard 'Thames'
Richard Despard aged 40
Philip R aged 29 farmer
Anna aged 20
Eliza aged 2.
Philip R was born in America, they returned to Ireland, then to the Isle of Man and then back to Ireland. Where Eliza was in 1851 I don't know but I was able to fill in this gem to the American side in exchange. It just shows to hold on to those 'possibles' just in case.