You mentioned in an earlier post that William had a sister called Cisily. This would tie him into the family of Thomas Bridson and Martha Walkington ( Walkinson) who worked at Ballakelly Farm in the parish of Santon ( St. Anne), 1881.
1891 has a William Bridson with the right age at Falmouth Cornwall which is at the end of the estuary to Truro. Maybe he was on his way?
Len Faragher