Thank you so much for your response.
I have Googled Gibraltar Records for Richard Cressey (who was born 1803 I believe) - but am not finding any record of him at all. English Censuses do, nevertheless, say that he was born on Gibraltar. Neither can I find any wife.
His five children were all born in Scotland and/or England between 1834 and 1853.
It all seems something of a (frustrating !) mystery.