Thanks Kite - I have been down that route but I don't seem to have kept a record of what I found
so will have investigate again. Although if I didn't make a note of anything it seems likely that I didn't find anything conclusive...
I think that a major problem is that the record keepers of the time heard Benson (their daughters baptism was recorded as Benson) instead of Benzing which doesn't make life any easier!