How'd you get on? , I've just drilled 6 holes (6mm Cobalt then 14mm HSS and a copious amount of this:
http://www.toolstation.com/shop/Automotive/d60/Lubricants+%26+Sprays/sd2795/Cutting+%26+Drilling+Cooling+Lubricant/p75018
They went fairly easily. Used a fairly unwieldy SDS drill as it spun...