If the boxes don't go inside the headlamp shell you bought the wrong one.
I have two sets in my headlamp shell, one in the dip beam and one in one of the mains. The best way to get decent lights on the S is to buy a cheap car kit with two sets of burners etc.
It all fits inside, wrapped in some of that perforated flubber matting to stop it rattling its way out.
The kits are designed to have the boxes outside the light unit with a hole cut in the rubber weather cap, hence the grommet. But on the S we have the luxury of a huge shell into which everything fits.
Cut the grommet off and ditch it and everything else should slip through the back of the shell.
Everything in the kit connects together with idiot'ish proof connectors with the two spade terminals going into the original H7 bulb connector and the weather cap completes the neat and invisible job.
Simples!
Bear in mind that most MoT testers (unlike mine) will fail a bike under the new rules introduced in 2018 for having an after market HID kit fitted. I would check with your local guy before rocking up for the test. It is simplicity itself to pull the burners and pop the bulbs back in for the test without disturbing the rest of the kit.
