I don't dunk biscuits as they tend to flop and the tea goes all mushy and I do like my tea unadulterated, however I do use bread to clean my plate if it seems appropriate - obviously I wouldn't do it if I was dining with Her Majesty or in posh polite company, but at home or with friends I do. I have a friend who eats from her knife - I am used to it (sort of) but do try to pretend it isn't happening and she is the sister of a very well known exPolitician, so heaven knows how he behaved when dining in high places if it was a family 'thing'.
Come to think of it he would have dined at BP so I expect HM looked away as I do and pretended it wasn't happening
(I suppose in some places it's ok to do that, but it just doesn't seem quite right to me.....)