Not 10mm2, that has quite a large flat face and isn't very flexable as I'm sure you are aware. Catch it on the face rather than the rounded edge and you'll drill it...
I like to keep my HSS drills sharp... Maybe I ought to invest in a =A32.99 set of market stall speacials for PB use. Through I think Pauls =
suggestion of lip and spur might be better, masonary and HSS will tend to tear any covering, hopefully the spur would cut it.