Yokel - I have tried soundex searches of every variant I can think of (Broughton, Browten, Braighton, Brayton, Brighton, Briton, Britain, Braden and so on) on freereg throughout Norfolk as well as searching through the images of the parish registers available on familysearch and the only candidate I have found so far for Susan Broughton in Litcham is Susanna Braighton of Marham.
amondg - That is a very good point about a licence - I had not considered it. On familysearch the banns records for Litcham begin in 1768, so I can't check for banns. At the moment I am ploughing my way slowly through marriage bonds in case I find one to indicate a parish of origin, but so far haven't found one.
Philip