Just found your post of Jan 2013. Better late than never! I too am stuck when it comes to the origins of Francis Philippe LONGUEHAYE. Fyi here is an extract from some research I did some time ago:
1) Francis Philippe LONGUEHAYE and Harriett WOODCOCK were married on 15.2.1797 at St. Botolph without Bishopsgate. Witnesses were Henry Woodcock (presumably the bride’s father) and a Sarah SIMPSON, which poses the question, where were Francis Philippe’s parents? Possibly back in France...?
In the 1841 census, Harriett Longuehaye, by now a widow, was living in Whitechapel Road and is shown as a “Boot and shoe maker”. At the time, she had as an apprentice her 15 year-old grandson George MOULDEN, (son of her daughter Victoire Angelica).
I believe Harriett Woodcock was born 1779 and died 1847. I am particularly interested in the Longuehaye French connection and will try to research the names given by your other respondent.
Do get back to me if you have made any progress in the last year.