GoGen, I am somewhat perturbed. You say that Richard Roberts married Susanna Finnis at St Leonard's on 21/7/78, witnesses Mary Mumbray & William Finnis.
I have produced a booklet of all Finnis' married, baptised and buried in St Margaret's and Deal and have a different date to yours, 26th Nov 1772 with Elizabeth Wells and John Roberts as witnesses.
My info is from the parish records. Where is yours from and have I made a silly mistake?
Kind Regards
AJ