"This would probably be an excellent product for plumbers, except the core drill bits are of no use whatsoever for drilling the right size holes. Let me see, 30mm core drill, that won't fit a 32mm waste pipe through it will it??
But wait, the 50mm bit, that'll do the job and leave a massive hole round the pipe, and a 40mm pipe too come to think of it.
Sadly it won't give you any room to wiggle a 50mm pipe through.