It’s Frejus mate.
I used to do that too, with Brian Yeardleys. You had to book-in much further down the hill with your ADR paperwork (I can’t remember where it was now, not to be able to tell you with any certainty). If they wanted to do a check of your load or equipment, they would do that there. You then went straight up to a holding area immediately before the tunnel, just before the toll booths, by-passing the normal holding area.
Like you say, you’d then wait for 2 or 3 more ‘■■■■■■ required’ loads to turn up, then go through in convoy with a beaconed up van.