Pevsner Dorset P  says Benjamin was the brother og the BBs but I think Colvin is probably the most reliable source so Benjamin Bastard I bet he suffered at school now has his own page but I thik I wil put a note in to say there is a difference of opinion  I always feel Pevsner is like a much loved great grand uncle  who though wise can be a little absent minded and wwanfering off at tangents  I dont know who else would know such an obscure fact