Thanks Sue & Frances,
My question was prompted by two quirks in the 1841 census.
1. John Christian is reprted in the census in Jarvis Street, Liverpool, living alone. This is the same address as that on his marriage certificate, when he married Agnes French at St. Nicholas Church in Liverpool on March 29 1841. Agnes however, is in the 1841 census in Rushen with her parents, under her maiden name. Their daughter, Margaret, was christened in Rushen three weeks later on June 27.
2. John fathered a son,with Ann Kermode. The son was christened in Rushen on November 15 1840. He and his mother appear twice in the Rushen census (he is called John Christian in the census). First his age is given as four months (they are at the same address as John and Ellinor Kermode) and then as six months at different address - I have been unable to find other names at this address.
A possible explanation for John and Agnes is that Agnes returned to Rushen to have her baby and that John deemed it wiser to remain in Liverpool.
I would be grateful if anyone can suggest what could have caused the duplication of Anne and John.
Bruce