Hi Sue,
Thank you for your reply. The confusion, on my part, is because of the following;- A few nights ago I googled--=Robert corkhill port e vullen----this revealed several choices, including= (pdf) 7.1 WILLIAM CLARKE---THE ISLE OF MAN FAMILY HISTORY SOCIETY, which follows on to 7.29 which gives the information that Thomas Corkill bapt 1st Jan 1841 married Margaret Kinrade 29th June 1861.

Although I have not doubted that Robert was the one in my line, I am certain that this Thomas has been mistakenly substituted for another. I have the Thomas/Jane Graham certificate.

The page has the name B Lawson 2008 towards the bottom.

Notice that I googled Robert Corkhill (with the 'h'). Missing out the 'h' produces a slightly different result.
Thanks again, Tony