All of mine were originals except the non notarised copy of my passport, but my wife submitted my birth certificate in lieu of a notarised copy of my passport, we had been advised that it would be okay to do that. I think it is safer to comply with the UKBA specified requirement so that you give them no excuses for refusal.
On bank statements, i got Nationwide to authenticate by stamp and signature all of the duplicates i received from them. I only had one or two originals, you see. Again, we were advised to do this.
