Yes Gizmo, 12mm plus the radius on the end, if it has one. This would make the man with the "dark glasses and clipboard" happy.
Please Mr Landyacht, can I have some minsup clips. The last lot you gave me "escaped" on the way home. I got to Norseman and the buggers had gone.

Those tapered drill bits ( 4mm to 26mm multi stage ones) are fantastic for drilling out washers. I use thin 8mm mudgard washers (large outside diameter 32mm) and drill them with this drill bit. Just use the very start of the next step up from 20mm to lightly debur them both sides. Works a treat!!!!