I'd like to install an outside tap and have bought a thru wall flange/ copper pipe. I want the pipe (15 mm diameter) to enter the interior of the house in a small gap (around 3 cm) between my washing machine and a fixed bench. How would I go about drilling this hole? I've read that you should drill from the outside of the house, but I think my margins for error are too small, and it would have to be perfectly straight. I've considered drilling from the inside of the house, but the bench is in the way! Any advice on how to proceed? Cheers!