I recently had to holesaw some awkwardly placed holes in trunking, like Steve I drilled all the pilot holes with a normal 6mm drill first then all the pilot drill had to do was locate in the pre-drilled hole. Alternatively in material where the pilot drill may wander or drill an off centre hole, make a template, secure it in position and drill without the pilot drill. Worked for me when I had to match the entry points on a CU with holes in the trunking. Also worked for me when core drilling for some conduit and I did not have a long enough pilot drill.

Richard