The earliest spelling of what became Banfield or Bamfield makes it unlikely to have meant bean field originally.
A Cornish language name meaning wheaten bread …
From barbarian? Or more likely Barbara.
Bean fields, bread and Barbara? Some rarer Cornish surnames
Cornish studies resources 
I would have thought that Bonfil = good son, and Bonfat = good fate (thus not the same name). Boniface, the more common spelling of the second name, was common at one time. And who wouldn’t wish for a bonfil or indeed bonnefille?
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Yes, I also assumed the two names had different origins. But in fact they appeared together in the same parishes which makes me think they were two developments from one original.
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Interesting. It’s possible that thete was a vogue for calling sons ‘Bon-‘, quite possibly in the same family which then became established
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There is a huge hospital in Johannesburg South Africa called Baragwanith not far what became Soweto and called Bara locally.This hospital was named Baragwanith as there was a Cornish colony in Johannesburg during the birth of the gold mines, my grandfather his brothers and cousins and my great Grandfather among them. The family name being Cadwell which you covered recently in rarer Cornish surnames.
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Fascinating about the South Africa connection.
I wonder if Barbary could refer to someone from the Barbary coast. It’s possible surely.
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