Hi, yeah the hole with the grommet is already there. There are several all along the sill.
The centre of the hole inside the van is about 30mm away from the van side. I used a 32mm hole saw and 23.5mm waste pipe.
Completely agree about the instructions from Evo, they may as well not bother sending any. It got easier the more you'd done because you had less bits to choose from. The first hinges did me! The different types! I tried them all.