Ah... I'm very sorry I don't have dimensions for drills smaller than No.80. To be honest, I thought the system stopped at 80. But I now find it continues up to No. 97. If I find out what the numbers are, I'll put them in. As for BA, it stands for British Association. Basically it was our attempt at 'metrification' but using imperial measurements. Nowadays it's only really used in the small nuts and bolds used by modellers.
Trevor